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Campbell Scientific SDM-INT8 Timer Instruction Manual PDF

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Summary of Content for Campbell Scientific SDM-INT8 Timer Instruction Manual PDF

IN ST

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SDM-INT8 8 Channel Interval Timer

Revision: 5/16

C o p y r i g h t 1 9 8 9 - 2 0 1 6 C a m p b e l l S c i e n t i f i c , I n c .

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General Prior to performing site or installation work, obtain required approvals and permits. Comply

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any attachments to tripods and towers. The use of licensed and qualified contractors is highly recommended.

Read all applicable instructions carefully and understand procedures thoroughly before beginning work.

Wear a hardhat and eye protection, and take other appropriate safety precautions while working on or around tripods and towers.

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Use only manufacturer recommended parts, materials, and tools.

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installing, constructing, using, or maintaining, or a tool, stake, or anchor, come in contact with overhead or underground utility lines.

Maintain a distance of at least one-and-one-half times structure height, 20 feet, or the distance required by applicable law, whichever is greater, between overhead utility lines and the structure (tripod, tower, attachments, or tools).

Prior to performing site or installation work, inform all utility companies and have all underground utilities marked.

Comply with all electrical codes. Electrical equipment and related grounding devices should be installed by a licensed and qualified electrician.

Elevated Work and Weather Exercise extreme caution when performing elevated work. Use appropriate equipment and safety practices. During installation and maintenance, keep tower and tripod sites clear of un-trained or non-

essential personnel. Take precautions to prevent elevated tools and objects from dropping. Do not perform any work in inclement weather, including wind, rain, snow, lightning, etc.

Maintenance Periodically (at least yearly) check for wear and damage, including corrosion, stress cracks,

frayed cables, loose cable clamps, cable tightness, etc. and take necessary corrective actions. Periodically (at least yearly) check electrical ground connections.

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Table of Contents PDF viewers: These page numbers refer to the printed version of this document. Use the PDF reader bookmarks tab for links to specific sections.

1. Overview ..................................................................... 1

2. Specifications ............................................................. 3

3. Connections ............................................................... 4

4. Power Supply Considerations .................................. 5

5. Programming the Datalogger .................................... 6

5.1 CRBasic Programming ........................................................................ 6 5.1.1 Instruction SDMINT8 ................................................................... 6 5.1.2 SDMSpeed Instruction .................................................................. 8

5.2 Edlog Programming (Instruction 101) .............................................. 9

6. Programming Details ............................................... 10

6.1 SDM Address ..................................................................................... 10 6.2 Input Configuration ............................................................................ 11 6.3 Functions ............................................................................................ 11 6.4 Output Option .................................................................................... 13

6.4.1 Rules for Averaging .................................................................... 13 6.4.2 Option 0: Execution Interval Averaging .................................... 16 6.4.3 Option 32768 or 0--: Continuous Averaging .............................. 16 6.4.4 Option nnnn or XXXX: Specified Averaging Interval .............. 17 6.4.5 Option nnnn or XXXX--: Capture All Events Until nnnn or

XXXX Edges On Channel 1 .................................................... 17 6.4.5.1 Option nnnn .................................................................... 17 6.4.5.2 Option XXXX--................................................................ 17

6.4.6 Option 9999--: Test Memory ..................................................... 18 6.5 Dest, Input Location, Multiplier, and Offset ...................................... 19 6.6 Edlog Output Format ......................................................................... 19

7. Program Examples ................................................... 20

7.1 CRBasic Program Example................................................................ 20 7.2 Edlog Program Examples ................................................................... 21

7.2.1 Cold Crank Engine Test - Capture All Events ............................ 21 7.2.2 Wind Speed Measurements - Execution Interval Averaging ...... 23 7.2.3 Brake Pressure and Wheel Speed Test - Capture All Events

and P23 Burst Mode ................................................................ 24

Appendices

A. Address Jumper ..................................................... A-1

Table of Contents

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B. Processing Time Limitations ................................. B-1

C. SDM-INT8 Input Schematic .................................... C-1

Figures 1-1. SDM-INT8 Front Panel ....................................................................... 1 1-2. Voltage Input Options, Edges, and Thresholds ................................... 2 3-1. Wiring Diagram ................................................................................... 5 6-1. Example of Multiple Beginnings and Endings .................................. 16 A-1. Address Selection ............................................................................ A-1

Tables 5-1. Bit Period Values ................................................................................ 9 5-2. Instruction 101................................................................................... 10 6-1. Input Frequency (kHz) at Which Processing Time Equals

Measuring/Storing Time ................................................................ 14 6-2. Sampling Interval (Seconds) to Accumulate 8000 Unprocessed

Events for Functions 1,2,6,7 .......................................................... 15 6-3. Definition of Test Memory Option Output........................................ 19

1

SDM-INT8 8 Channel Interval Timer 1. Overview

FIGURE 1-1. SDM-INT8 Front Panel

SDM-INT8 8 Channel Interval Timer

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The 8 channel Interval Timer (SDM-INT8; see FIGURE 1-1) is a measurement module which outputs processed timing information to a 21X, CR10(X), CR23X, CR800, CR850, CR1000, CR3000, CR5000, or CR9000(X) datalogger. Each input channel is programmed to detect transitions from low or high level voltage inputs (FIGURE 1-2). Period, pulse width, frequency, counts, and time intervals are output to the datalogger for further processing/logging.

FIGURE 1-2. Voltage Input Options, Edges, and Thresholds

In CRBasic, the SDMINT8 instruction is used to program and control the SDM-INT8; in Edlog, Instruction 101 is used. These instructions, address, command, and receive data from the SDM-INT8 through three ports on the datalogger (see Section 3, Connections (p. 4)). Multiple SDM-INT8s, each with a unique address, may be controlled by one datalogger.

The SDM-INT8 has its own processor which enables it to make measurements and process data while the datalogger is performing other tasks. Each of the 8 channels may be independently programmed to detect either rising or falling edges and perform the following functions (Section 6.2, Input Configuration (p. 11)).

The SDM-INT8 can capture timing events with 1 microsecond resolution over a maximum range of 16.77 seconds. Timing on different channels can be compared to within 1 microsecond. At the same time, the datalogger can be executing various analog measurements, but the exact time these measurements are taken is subject to the dataloggers timing resolution. Section 7.2.3, Brake Pressure and Wheel Speed Test - Capture All Events and P23 Burst Mode (p. 24), discusses the possibilities and limitations of synchronizing SDM-INT8 and datalogger measurements.

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2. Specifications Operating voltage: 9.6 V to 16 Vdc

Current drain: 13 to 20 mA active 400 microamp quiescent

Environmental: 25 to 50 C 0 to 90% RH (non-condensing)

Number of channels: 8

Maximum timing measurement: 16.7 seconds

Resolution: 1 microsecond

Dimensions: 13 x 20 x 2 cm (8 x 5 x 1 in)

Weight: 635 g (1.4 lb)

Input voltage option per channel: high level, low level

High Level Voltage Input

Minimum pulse width: 2 microseconds

Signals edges Rising: transition from < 1.5 to > 3.5 volts Falling: transition from >3.5 to<1.5 volts Maximum input voltage: 20 volts

Maximum frequency: 5.1 kHz when using Averaging Options 10 kHz when Capturing All Events

The Low Resolution Frequency function allows higher frequencies to be measured if it is used on all programmed channels with Execution Interval Averaging. Maximum frequency is dependent on the number of channels programmed, as shown below:

No. of Channels Max Freq (kHz)

1 42.5

2 17.5

3 11.0

4 8.6

5 5.2

6 4.8

7 4.5

8 4.28

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Low Level Voltage Input

Minimum AC voltage: 20 millivolts RMS

Input hysteresis: 11 millivolts

Maximum AC voltage: 20 volts RMS

Minimum frequency: 1 Hz

Maximum frequency

Minimum AC Voltage RMS

Max Frequency (Hz)

20 mV 100

50 mV 400

150 mV 1000

2.5 V - 20 V 4000

3. Connections The CABLE5CBL-L cable connects the SDM-INT8 to a datalogger. The datalogger-to-SDM-INT8 connections are shown in FIGURE 3-1. Please note that the SDM-INT8 connects to the CR9032 CPU module of the CR9000X and the CR9080 PAM module of the CR9000. SDM-INT8s are shipped from the factory with a 10K Ohm resistor attached to the terminal strip for the convenience of 21X user. This resistor is necessary only when the SDM-INT8 is used with a 21X datalogger.

Except for the 21X, the order in which the datalogger and SDM-INT8 connections are made is critical. The datalogger cases and wiring panel bracket are at datalogger ground. To avoid accidentally shorting 12 V to the case, connect the 12 V first then the ground. To prevent voltages in excess of 5 V from entering the dataloggers SDM ports (C1 to C3 or SDM- C1 to SDM-C3), the ports are wired after connecting the ground lead.

For the 21X, a 10K resistor is wired between Control Port 1 and single ended input 1 (1H). The order in which 21X/ SDM-INT8 connections are made is not critical.

The CABLE5CBL-L has a user-specified length. A 1-ft length should be sufficient when both datalogger and SDM-INT8 are housed in an ENC12/14 enclosure; a 2-ft length may be required if the datalogger and SDM-INT8 are housed at opposite ends of an ENC16/18. The total cable length for all SDMs should be as short as possible and preferably does not exceed 20 feet. Longer lead lengths may be possible for CRBasic dataloggers if the SDMSpeed instruction is used (see Section 5.1.2, SDMSpeed Instruction (p. 8)). Long lead lengths may prevent communication.

CAUTION

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The signal input lines of the SDM-INT8 are protected against the continuous connection of voltages up to 20 VDC and against high voltage electrostatic discharge. However, where there are long cable runs (>3 m) to the sensor and particularly when the cables run outside, some extra protection may be required for these inputs to protect the inputs against high energy surges, as may be induced by lightning. Please contact Campbell Scientific for further advice.

10K OHM RESISTOR

CR800, CR850, CR9032

(CR9000X), CR9080

(CR9000), CR10(X), CR23X,

or CR1000

CR3000, CR5000

12V G

SDM-C3 SDM-C2 SDM-C1

FIGURE 3-1. Wiring Diagram

4. Power Supply Considerations The datalogger's power supply is typically used to power the SDM-INT8, however, an auxiliary supply may be used as shown in FIGURE 3-1. When selecting a power supply, consideration must be given to the active current drain and the active time of the SDM-INT8. With two exceptions, if the SDM- INT8 is programmed it is drawing 13 to 20 mA. The two exceptions are:

When the Specified Averaging Interval (Section 6.4.4, Option nnnn or XXXX: Specified Averaging Interval (p. 17)) is selected, the SDM-INT8 enters the quiescent current drain state (400 microamp current drain) after returning the results to the datalogger.

If the interval between executions of Instruction 101 exceeds 16.77 seconds, the SDM-INT8 enters the quiescent current drain state.

If a 21X datalogger is used to power the SDM-INT8, all low level analog measurements (thermocouples, pyranometers, etc.) must be made

CAUTION

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differentially. This is due to slight shifts in the ground potential on the terminal strip when the 21X is used to power external devices.

5. Programming the Datalogger The datalogger is programmed using either CRBasic or Edlog. Dataloggers that use CRBasic include our CR800, CR850, CR1000, CR3000, CR5000, and CR9000(X). Dataloggers that use Edlog include CR7, CR10(X), CR23X, and 21X. Both CRBasic and Edlog are provided in LoggerNet and PC400.

5.1 CRBasic Programming 5.1.1 Instruction SDMINT8

The SDMINT8 instruction is used to program and control the SDMINT8 interval timer module. Description of the instruction follows.

Syntax SDMINT8 (Dest, SDMAddress, Config8_5, Config4_1, Funct8_5, Funct4_1, OutputOpt, CaptureTrig, Mult, Offset)

Dest: Dest is used to specify the array where the results of the instruction are stored. For all output options except Capture All Events (-nnnn), the Dest argument should be a one dimensional array with as many elements as there are programmed SDM-INT8 channels. If the Capture All Events output option is selected, the Dest array must be two dimensional. The magnitude of first dimension should be set to the number of functions (up to 8), and the magnitude of the second dimension should be set to at least the maximum number of events to be captured. The values will be loaded into the array in the sequence of all of the time ordered events captured from the lowest programmed channel to the time ordered events of the highest programmed channel.

SDMAddress: This parameter is used to define the address of the SDM-INT8 with which to communicate. Valid SDM addresses are 0 through 14 (factory default is 0). Address 15 is reserved for the SDMTrigger instruction. If the Reps parameter is greater than 1, the datalogger will increment the SDM address for each subsequent device that it communicates with. See Section 6.1, SDM Address (p. 10), for further detail.

CRBasic dataloggers use base 10 when addressing SDM devices. Edlog programmed dataloggers (e.g., CR10X, CR23X) used base 4 for addressing.

Config8_5: The Config8_5 parameter is a four-digit code used to configure channels 5 through 8 on the SDM-INT8. Each input channel can be configured for either high or low level voltage inputs and for rising or falling edges. The digits represent the channels in descending order from left to right (e.g., 8 7 6 5). As an example, the code 0303 would program channels 8 and 6 to capture the rising edge of a high level voltage, and channels 5 and 7 to capture the falling edge of a low level voltage. See Section 2, Specifications (p. 3), for information about the specification requirements of high and low level voltage signals.

NOTE

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Code Description 0 High level, rising edge 1 High level, falling edge 2 Low level, rising edge 3 Low level falling edge

Config4_1: The Config4_1 parameter is a four-digit code used to configure channels 1 through 4 on the SDM-INT8. It is identical in function to Config8_5. The digits represent the channels in descending order from left to right (e.g., 4 3 2 1).

Function8_5: The Function8_5 parameter is a four digit code used to program the timing function of channels 5 through 8. Similar to the Config parameters, digits represent the channels in descending order from left to right (e.g., 8 7 6 5). See Section 6.3, Functions (p. 11), for further details about these functions.

Code Description 0 No value returned 1 Period (ms) between edges on the programmed channel 2 Frequency (kHz) of edges on the programmed channel 3 Time (ms) between an edge of the previous channel and an edge of

the programmed channel 4 Time (ms) between an edge on Channel 1 and edge on the

programmed channel 5 Number of edges on channel 2 since last edge on channel 1 using

linear interpolation 6 Low resolution frequency (kHz) of edges on programmed channel 7 Total count of edges on programmed channel since last interrogation 8 Number of edges on channel 2 since last edge on channel 1 without

linear interpolation

Function4_1: The Function4_1 parameter is a four-digit code used to program the timing function of channels 1 through 4. It is identical in function to Function8_5. The digits represent the channels in descending order from left to right (e.g., 4 3 2 1).

OutputOpt: The OutputOption parameter is a numeric code that is used to select one of the five different output options. The selected option will be applied to all of the SDM-INT8 channels. A brief explanation is given below for each code. See Section 6.4, Output Option (p. 13), for detailed explanations of each option.

0: Stores an average of the event data since the last time that the SDM-INT8 was interrogated by the datalogger. If no edges were detected, 0 will be returned for frequency and count functions, and 99999 will be returned for the other functions. The SDM-INT8 ceases to capture events during communications with the datalogger, thus some edges may be lost.

32768: Performs continuous averaging, which is utilized when input frequencies have a slower period than the execution interval of the datalogger. If an edge was not detected for a channel since the last time that the SDM- INT8 was polled, then the datalogger will not update the Dest for that channel. The SDM-INT8 will capture events even during communications with the datalogger.

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nnnn: Averages the input values over "nnnn" milliseconds. The datalogger program is delayed by this instruction while the SDM-INT8 captures and processes the edges for the specified time duration and sends the results back to the datalogger. If no edges were detected, 0 will be returned for frequency and count functions, and 99999 will be returned for the other functions.

-nnnn: Instructs the SDM-INT8 to capture all events until "nnnn" edges have occurred on channel 1, until the datalogger addresses the SDM-INT8 with the CaptureTrig argument true, or until 8000 events have been captured. When the CaptureTrig argument is true, the SDM-INT8 will return up to the last nnnn events for each of the programmed SDM-INT8 channels, reset its memory, and begin capturing the next nnnn events. The SDM-INT8 waits for the first edge on channel 1 as a trigger to start making measurements. The Dest parameter must be dimensioned large enough to receive the captured events.

-9999: Initiates a self-memory test of the SDM-INT8. A numeric code is returned to indicate the results of the test.

Code Description 0 Bad ROM -0 Bad ROM and bad RAM

positive integer: Good ROM (value returned is the ROM signature) and good RAM

negative integer: Good ROM (value returned is the ROM signature) and bad RAM

CaptureTrig: This argument is used when the Capture All Events output option is used. When CaptureTrig is true, the SDM-INT8 will return the last nnnn events.

Mult: The multiplier with which to scale the raw data.

Offset: The offset that is to be applied to the raw data.

This instruction must NOT be placed inside a conditional statement when running in pipeline mode.

5.1.2 SDMSpeed Instruction The SDMSpeed instruction is used to change the bit period that the datalogger uses to clock the SDM data. Slowing down the clock rate may be necessary when long cable lengths are used to connect the datalogger and SDM devices.

The syntax of this instruction is as follows:

SDMSpeed (BitPeriod)

The BitPeriod argument can be an integer or a variable. If the SDMSpeed instruction is not in the program, a default bit period is used. If 0 is used for the argument, the minimum allowable bit period is used. TABLE 5-1 shows the default, minimum allowable, and maximum bit period for each of our CRBasic dataloggers.

NOTE

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TABLE 5-1. Bit Period Values

Datalogger

Default Bit Period

Minimum Allowable Bit Period

Maximum Bit Period

CR800, CR850 26.04 sec 8.68 sec 2.2 msec

CR1000 26.04 sec 8.68 sec 2.2 msec

CR3000 26.04 sec 8.68 sec 2.2 msec

CR5000 30 sec 8 sec 3 msec The equation used to calculate the bit rate depends on the datalogger used. The datalogger will round down to the next faster bit rate.

Equation for CR800, CR850, and CR1000:

bit_rate=INT((k*72)/625)*Resolution

Where: k= the value entered in BitPeriod

Resolution=8.68 microseconds

Equation for CR3000:

bit_rate=INT((k*144)/625)*Resolution

Where: k= the value entered in BitPeriod Resolution= 4.34 sec.

Equation for CR5000:

bit_rate=INT(k*20)*Resolution

Where: k= the value entered in BitPeriod Resolution=50 nsec.

5.2 Edlog Programming (Instruction 101) In Edlog, Instruction 101 (see TABLE 5-2) is used to address, command, and retrieve data from the SDM-INT8. On the first execution of Instruction 101, the SDM-INT8 is programmed. Subsequent executions of Instruction 101 may command the SDM-INT8 to send its processed data to the datalogger or to reinitialize its measurement process. If multiple SDM-INT8s are connected to a datalogger, each SDM-INT8 must have a corresponding Instruction 101 and a unique address.

The datalogger tracks the first time a 101 Instruction is executed to know if the associated SDM-INT8 is programmed or not. If two or more 101 Instructions are used to address the same SDM-INT8, the first execution of each Instruction will program the SDM-INT8 returning no data. If the SDM-INT8 must be called more than once per datalogger execution interval, place Instruction 101 in a subroutine and call the subroutine when Instruction 101 must be executed. The SDM-INT8 is programmed on the first call, with data being returned on subsequent calls.

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TABLE 5-2. Instruction 101

Parameter Data Description Type 01: 2 Address (Section 6.1, SDM Address (p. 10)) 02: 4 *Input config; channels 8,7,6,5 03: 4 *Input config; channels 4,3,2,1 04: 4 **Function; channels 8,7,6,5 05: 4 **Function; channels 4,3,2,1 06: 4 ***Output option 07: 4 Loc 08: FP Mult 09: FP Offset Execution time: 2.3 ms + 1.65 ms/value + averaging interval (See Appendix B, Processing Time Limitations (p. B-1), to

estimate processing time on higher frequency signals) Intermediate Storage: 1 location * Input configurations (Section 6.2, Input Configuration (p. 11)): 0 = high level, rising edge 1 = high level, falling edge 2 = low level, rising edge 3 = low level, falling edge **Functions (Sec. 6.3): 0 = no value returned 1 = period in ms 2 = frequency in kHz 3 = time since previous channel is ms 4 = time since channel 1 in ms 5 = counts on channel 2 since channel 1 6 = low resolution frequency in kHz 7 = counts 8 = integral counts on channel 2 since channel 1 *** Output (Sec. 6.4): 0 Execution interval averaging 0- - Continuous averaging XXXX Specified averaging interval in ms, XXXX>0 XXXX- - Capture all events until XXXX edges of channel 1

(0 <8000) 9999- - Test memory

6. Programming Details 6.1 SDM Address

The SDM-INT8 is enabled by an address sent from the datalogger. A terminal block located inside the SDM-INT8 has two jumpers which define the SDM- INT8 address. The address defined by the jumpers must match the address entered into SDMINT8 or Instruction 101. The jumpers are set at the factory for address 00. If the jumpers have not been changed, the SDM address entry is 00. Each SDM-INT8 connected to the datalogger must have a unique address. See Appendix A, Address Jumper (p. A-1), for details on changing the address.

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6.2 Input Configuration Each of the 8 input channels can be configured for either high level or low level voltage input, and for rising or a falling edge detect (see FIGURE 1-2). One digit (0,1,2, or 3) is specified to configure each channel, as shown below.

0 = high level, rising edge 1 = high level, falling edge 2 = low level, rising 3 = low level, falling

Example: Channel 1 thru 5: high level, rising edge Channel 6: high level, falling edge Channel 7 and 8: low level, rising

02:2210 (channels 8,7,6,5) 03:0000 (channels 4,3,2,1)

6.3 Functions Each of the 8 channels can be programmed independently for various timing functions. Channel functions are programmed with one digit (0,1,2,3,4,5,6,7, or 8) for each channel. Functions 0 through 8 are described below.

0 - no value

1 - Period (ms)-- The time between signal edges on this channel in milliseconds.

2 - Frequency (kHz)-- The frequency of signal edges on this channel in kHz. Frequency is calculated from a measurement of period.

3 - Time since previous channel (ms)-- The time between the signal edge on the next lower numbered channel and the signal edge on this channel is in milliseconds. This function can be used to measure pulse width by connecting the signal to two adjacent channels programmed with opposite edge detect directions.

4 - Time since channel 1 (ms)-- The time between the signal edge on channel 1 and signal edge on this channel is in milliseconds.

5 - Count on channel 2 since channel 1-- The number of signal edges on channel 2 between channel 1's signal edge and this channel's signal edge. Linear interpolation is used to derive a fraction of a count at both the beginning and end of counting

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6 - Low resolution frequency (kHz)-- For this function to return low resolution data, it must be the only function used in the instruction. If this is not the only function used in the instruction, it returns high resolution data, the same as Function 2.

Higher frequencies may be measured if fewer channels are used (see Section 2, Specifications (p. 3)).

For this function, any data value less than 1 is returned as 0. This must be considered when calculating the multiplier and offset (Parameters 8 and 9).

The frequency is returned to the datalogger in a low resolution format (16- bit floating point). This format allows for a range of positive real numbers between 1 and 65480 with 4-digit resolution on values whose mantissa is less than 8192. Three (3) digit resolution is given on values with mantissas greater than or equal to 8192.

Fewer bits are transferred to the datalogger in the 16-bit format, speeding up the instruction execution time by 0.3 ms per value.

7 - Counts-- "Counts" will always return an integer value when Instruction 101 is executed. The value will be the number of edges that have occurred since the last execution of Instruction 101. If no edges have occurred, a zero is returned. This function does not work with the Capture All Events Output Option.

If counts are being totalized by the datalogger, use the Continuous Averaging Output with "Counts" to avoid missing any counts (Section 6.4.3, Option 32768 or 0--: Continuous Averaging (p. 16)).

8 - Integral counts on chnl 2 since chnl 1-- Same as function 5 with no linear interpolation.

Example: The SDM-INT8 is used in an automotive test to measure crank angle, engine RPM when spark #1 fires, and fuel injector duty cycle. Parameters 2 and 3 are programmed as follows:

Parameter 2:0001 (channels 8,7,6,5) Parameter 3:0000 (channels 4,3,2,1)

Channel 1: crank shaft reference pulse, rising edge (0) Channel 2 pulse from the flywheel teeth, rising edge (0) Channel 3: pulse from spark #1, rising edge (0) Channel 4: fuel injector pulse, rising edge (0) Channel 5: fuel injector pulse, falling edge (1)

Parameters 4 and 5 are programmed for the following functions:

Parameter 4:0003 (channels 8,7,6,5) Parameter 5:2502 (channels 4,3,2,1)

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Channel 1: frequency (2) Channel 3: counts on channel 2 since channel 1 (5) Channel 4: frequency (2) Channel 5: time since previous Channel (3) Channel 2,6,7,8: none (0)

Channel 1: RPM may be calculated from crankshaft frequency.

Channel 3: Flywheel teeth count between the crankshaft reference pulse, and the spark gives reference to the crank angle.

Channel 4: The frequency of fuel injection may be multiplied by channel 5s positive pulse width to yield fuel injector duty cycle. The multiplication is not performed in the SDM- INT8.

Channel 5: Time of the positive pulse width of the fuel injector is given in milliseconds.

6.4 Output Option An important conceptual difference between Output Options and Functions is that one Output Option is selected per Instruction (SDMINT8 or Instruction 101) and applied to data from all channels. Functions are applied to individual channels.

6.4.1 Rules for Averaging This section applies to only those Output Options which perform averaging (i.e., 0, 32768, nnnn in SDMINT8 or 0, 0--, XXXX in Instruction 101).

Averaging is performed on events which are defined by at least two edges. For example, to average a period two rising edges are required to define a period. To average the time since the previous channel, an edge on the previous channel followed by an edge of the channel programmed for time since previous channel is required.

No averaging is done on channels programmed for Function 7, "Counts". Channels programmed for counts do not require two edges for an event. Single edges of the specified direction are counted.

The maximum interval that the SDM-INT8 can time is 16.77 seconds. Edges which are separated by a time longer than this will result in a false measurement.

In all Output Options that average, the SDM-INT8 is storing measurements and processing. The measuring/storing task takes priority over the processing task. If the input signal exceeds a certain frequency, processing will lag behind measuring/storing. TABLE 6-1 provides the maximum average frequency at which the processing task keeps up with the measuring/storing task.

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TABLE 6-1. Input Frequency (kHz) at Which Processing Time Equals Measuring/Storing Time

N 1,2,6,7 3 4 5 8

1 * 3.4 3.7 0.14 - 0.05F2 3.4 - 0.81F2 2 3.5 1.6 1.7 0.07 - 0.02F2 1.6 - 0.38F2 3 2.1 0.99 1.1 0.05 - 0.02F2 0.99 - 0.24F2 4 1.4 0.70 0.76 0.04 - 0.01F2 0.70 - 0.17F2 5 .99 0.53 0.57 0.03 - 0.01F2 0.53 - 0.13F2 6 .75 0.42 0.45 0.02 - 0.01F2 0.42 - 0.10F2 7 .59 0.34 0.37 8 .47 0.28 0.30

N = Number of channels measuring given Function * = Greater than the maximum input frequency of 5.1 kHz F2 = Average input frequency on channel 2

See Appendix B, Processing Time Limitations (p. B-1), to formulate the equations used to generate TABLE 6-1. Frequencies show in TABLE 6-1 are for "worst case" conditions. Faster input frequencies are possible depending on the phase relationship of the channel to channel signal.

With Options 0, 32768, and 0--, the average returned to the datalogger is the most recently processed average when the SDM-INT8 is addressed. If processing lags measuring/storing, the number of samples used in the average is reduced as is the effective averaging interval. For functions that average, this is not a problem, assuming the input frequency does not change significantly over the sampling interval. It is a problem if counts are being totalized (Function 7, Output Option 32768 or 0--). In this case the count will intermittently be low (Section 6.4.3, Option 32768 or 0--: Continuous Averaging (p. 16)).

The Specified Averaging Interval Option (nnnn or XXXX) uses all events captured over the specified interval to calculate an average. If the processing tasks gets behind the measuring/storing task, the additional time required to process all the edges is taken at the expense of the execution time (refer to TABLE 6-1).

Due to finite memory in the SDM-INT8, when processing lags behind by 800 edges, the measuring/storing task is suspended for that interval. For Option nnnn or XXXX to average over the entire specified interval, the interval must be short enough to prevent the processing tasks from getting behind by more than 8000 edges. TABLE 6-2 gives the sampling interval at which 8000 unprocessed events will accumulate for a given input frequency.

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TABLE 6-2. Sampling Interval (Seconds) to Accumulate 8000 Unprocessed Events for Functions 1,2,6,7

Input Number of Channels Freq. kHz 3 4 5 6 7 8

1.1 5.26 1.3 7.97 2.84 1.48 1.5 4.21 1.81 1.00 1.7 2.67 1.26 .73 1.9 5.62 1.87. .93 .55 2.1 3.68 1.38 .72 .43 2.3 2.64 1.07 .57 .35 2.5 2.00 .86 .47 .29 2.7 6.55 1.57 .7 .39 .24 2.9 4.64 1.27 .58 .33 .20 3.1 3.50 1.05 .49 .28 .18 3.3 2.76 .88 .42 .24 .15 3.5 2.24 .75 .37 .21 .13 3.7 1.86 .65 .32 .19 .12 3.9 1.57 .57 .28 .17 .11 4.1 1.35 .50 .25 .15 .10 4.3 8.91 1.17 .45 .23 .13 .09 4.5 6.73 1.03 .40 .20 .12 .08 4.7 5.33 .91 .36 .19 .11 .07 4.9 4.36 .81 .33 .17 .1 .06 5.1 3.65 .73 .30 .15 .09 .06

Sampling intervals shown in TABLE 6-2 are for "worst case" conditions. Longer sampling intervals are possible depending on channel phase relationships. See Appendix B, Processing Time Limitations (p. B-1), to calculate maximum intervals for other Functions.

When the low resolution frequency function is used, summing is not required; an average over the full interval is always available.

In all options that do averaging, the functions that involve time or count differences between different channels (time since channel 1, counts on 2 since 1, and time since previous channel) behave as follows: if there are multiple beginning edges and/or ending edges, i.e., more than 1 beginning edge per ending edge or vice versa, then only the last of the beginning edges and the first of the ending edges are used in the average. For example, assume all detection is on rising edges, and the function is counts on channel 2 since 1 for channel 3. A diagram of this example is presented in FIGURE 6-1. Multiple beginning edges are shown on channel 1, and multiple ending edges on channel 3. In this example, only 2 edges are used in the average.

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FIGURE 6-1. Example of Multiple Beginnings and Endings

6.4.2 Option 0: Execution Interval Averaging When Option 0 is selected, the result from each channel is a value averaged over the interval since the SDM-INT8 was previously addressed. Normally this would be the execution interval. The value returned to the datalogger is the average at hand when the SDM-INT8 is addressed. If processing lags the measuring/storing task, the unprocessed events are not used in the averaging and are deleted from memory.

With Option 0, the datalogger should be programmed to execute Instruction 101 at least every 16.77 seconds while making measurements. If this period is exceeded, the SDM-INT8 enters a low power standby mode and events are missed.

If no event occurs during the interval, 0 is returned for frequency and count functions, and 99999 (infinity) is returned for the other functions.

With Option 0, the SDM-INT8 ceases to capture events while it is communicating with the datalogger and reinitializes its measurement operation afterwards. Thus, edges that occur during this communication period (generally 2.3 ms + 1.7 ms/value) are ignored by the SDM-INT8.

6.4.3 Option 32768 or 0--: Continuous Averaging The Continuous Averaging Option is similar to Option 0 with the following differences:

1. The SDM-INT8 keeps capturing input edges during communication with the datalogger. If the time required for processing is less than or equal to the time required for measuring/storing (see TABLE 6-1), events will not be missed.

2. The datalogger will not update the input location of a channel that has not had an event since the last time the SDM-INT8 was addressed.

With the Continuous Averaging option, the datalogger should be programmed to execute SDMINT8 instruction or Instruction 101 at least every 16.77 seconds while making measurements. If this period is exceeded, the SDM- INT8 enters a low power standby mode and events are missed.

The Continuous Averaging option is designed for input frequencies or intermittent signals that are at a slower rate than the execution interval of the datalogger. It is also used for totalizing counts.

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Assume the input frequency is 0.5 Hz, and the execution interval of Instruction 101 is 10 Hz. The datalogger input location is updated at about 0.5 Hz if a change occurred, not every time the SDM-INT8 is addressed.

An example of an intermittent signal is a Cub Scout Pinewood Derby where the measured event is the elapsed time of a race, but several minutes separate each heat. Three cars per heat are gravity powered down a straight track. The start of the race triggers an edge on SDM-INT8 channel 1. The three cars each trigger an edge on separate channels as they cross the finish line. Function 4 is used to measure "time since channel 1" to provide the elapsed time for each car. The datalogger can be addressing the SDM-INT8 as often as desired with this option, but variables or input locations will only be updated at the finish of a new heat.

The Continuous Averaging Option is used for totalizing counts (Function 7) because the SDM-INT8 continues to measure and store events even when communicating with the datalogger. However, counts will be missed if the measuring/storing task exceeds the processing task (see TABLE 6-1).

6.4.4 Option nnnn or XXXX: Specified Averaging Interval Option nnnn or XXXX is used to average over an exact interval when the instruction is executed. The averaging interval is specified in units of milliseconds. The datalogger program is delayed for the specified interval while the SDM-INT8 captures, edges, plus the extra time required for processing if the processing task lags behind the measuring/storing task. After returning the results to the datalogger, the SDM-INT8 enters the low power standby mode (400 microamp current drain), increasing battery life.

Like Option 0, this option will return 0 for frequency and count functions and 99999 for all functions if no result is available during the specified interval, i.e. the signal was too slow.

6.4.5 Option nnnn or XXXX--: Capture All Events Until nnnn or XXXX Edges On Channel 1

6.4.5.1 Option nnnn Option nnnn instructs the SDM-INT8 to capture all events until nnnn edges have occurred on channel 1, until the datalogger addresses the SDM-INT8 with the Capture Trigger argument true, or until 8000 events have been captured. When the CaptureTrig argument is true, the SDM-INT8 will return up to the last nnnn events for each of the programmed channels, reset its memory, and begin capturing the next nnnn events. The SDM-INT8 waits for the first edge on channel 1 as a trigger to start making measurements. The Dest parameter must be dimensioned large enough to receive the captured events.

6.4.5.2 Option XXXX-- Option XXXX-- outputs all available timing information with no averaging. "All events" means that every occurrence of each programmed functions is recorded, i.e., each period, each pulse width, etc. as opposed to one averaged value.

Since the number of values returned may be variable, making it difficult to assign a fixed number of input locations, the Capture All Events Option

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outputs data directly to the datalogger's Final Storage when Instruction 101 is executed.

If the Output Flag is not set when the instruction is executed, the datalogger commands the SDM-INT8 to start measuring, and no results are returned. If the Output Flag is set, the datalogger retrieves the events that have been stored since the last time the instruction was executed and stores them directly in Final Storage. Data from the lowest numbered programmed channel are output first. Each subsequent channel's output has a new array ID which is incremented by 1. When all data are transferred, the SDM-INT8 starts its measuring process again.

The SDM-INT8 waits for the first edge on channel 1 as a "trigger" to start making measurements. It will then capture edges until XXXX edges on channel 1, or until the datalogger again addresses it, or until 8000 edges have been captured, whichever happens first. Output will not be returned until Instruction 101 is executed with the Output Flag set, even if the edge limits are reached.

With this option, Instruction 101 does not have to be executed every 16.77 seconds. The SDM-INT8 will continue to measure without entering the low power mode until 8000 edges are captured. Events being measured by the SDM-INT8 must not exceed 16.77 seconds, or false measurements will be returned. The maximum input is 10 kHz for all channels.

On a 10 second one-shot test, for example, Instruction 101 could be executed with the Output Flag cleared and then executed 10 seconds later with the Output Flag set. Or, Instruction 101 could be placed in a subroutine and called from different points in the programs.

For a 10 second test repeated every 10 seconds, the Output Flag could be set every time the instruction is executed.

Analog measurements can be made by the datalogger while the SDM-INT8 is capturing events. To some degree, and with caution, datalogger measurements can be synchronized with SDM-INT8 measurements. For example, the datalogger can execute the Burst Mode after executing Instruction 101 and trigger on the same signal that triggers channel 1 of the SDM-INT8. The caution is that the trigger on channel 1 cannot occur before the datalogger has a chance to enter the Burst Mode. To synchronize datalogger and SDM-INT8, the Burst Mode should be ready and waiting for the "trigger".

6.4.6 Option 9999--: Test Memory Option 9999-- causes the SDM-INT8 to do a self-memory test instead of measure and process timing functions. The signature of the SDM-INT8 PROM is returned to the datalogger's Input Location of the initial execution of the instruction. If the value is negative it indicates bad RAM; 0 indicates a bad PROM, as shown in TABLE 6-3.

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TABLE 6-3. Definition of Test Memory Option Output

Output Definition

positive integer = ROM signature, good RAM negative integer = ROM signature, bad RAM 0 = bad ROM -0 = bad ROM, bad RAM

A result of executing Option 9999-- is that the program residing in the SDM- INT8 is deleted, and the SDM-INT8 goes into the low current drain standby mode. To initiate SDM-INT8 measurements, SDMINT8 or Instruction 101 must be executed without 9999--.

6.5 Dest, Input Location, Multiplier, and Offset For the SDMINT8 instruction, Dest is used to specify the array where the results of the instruction are stored. For all output options except Capture All Events (-nnnn), Dest argument should be a one dimensional array with as many elements as there are programmed SDM-INT8 channels. If the Capture All Events output option is selected, the Dest array must be two dimensional. The magnitude of the first dimension should be set to the number of functions (up to 8), and the magnitude of the second dimension should be set to at least the maximum number of events to be captured. The values will be loaded into the array in the sequence of all of the time ordered events captured from the lowest programmed channel to the time ordered events of the highest programmed channel.

For Instruction 101 the input location is designated in parameter 7. Except for the Capture All Events Options, data from the SDM-INT8 are returned to the starting input location in ascending programmed channel order. Output from Capture All Events is returned directly to Final Storage in the datalogger.

Except for the "Test memory" option, the multiplier and offset are applied to all results by the SDM-INT8 before they are returned to the datalogger.

For Low Resolution Frequency (Function 6), any value less than 1 is returned as 0. This must be considered when calculating the multiplier and offset.

6.6 Edlog Output Format The Output Option specifies the format of the output received by the datalogger. The format of the three options that do averaging (Options 0, 0--, and XXXX) are identical. A single value for each programmed channel is stored in consecutive input locations starting at the location specified in parameter 7, Instruction 101. If only three SDM-INT8 channels are programmed, then only three Input Locations will be utilized. Output Processing Instructions, such as Instruction 70 (Sample) must be used to store the results in Final Storage.

When using the Capture All Events Option (no averaging), the data are directed to Final Storage of the datalogger rather than Input locations. The first execution of Instruction 101 will program the SDM-INT8. Subsequent executions of Instruction 101 with the Output Flag set will output all events to

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Final Storage. If the Output Flag is not set, the SDM-INT8 will be reinitialized without returning any data. The output returned for each programmed channel will be all events that have occurred since the last execution of Instruction 101. Each channel will have a unique Array ID. If other Output Processing Instructions precede Instruction 101, the first channel's data will be grouped with the previous Final Storage data (i.e. same Array ID.). This first Array ID will be incremented by one for each additional programmed channel.

Output for the Test Memory Option is a single value returned to the specified input location.

7. Program Examples These examples are given to demonstrate concepts. The starting conditions for each example are followed by a datalogger program. These examples are not to be used verbatim.

7.1 CRBasic Program Example Measure 2 Wind Sentry Anemometer (03101) on CR1000 pulse channel P1 and P2 and measure 5 Wind Sentry Anemometer (03101) connected to the SDM-INT8 channel 1 through channel 5. See Section 5.1.1, Instruction SDMINT8 (p. 6), for a description of the CR1000 SDMINT8 instruction parameters.

Wiring CR1000 SDMINT8 12 V 12 V Gnd Gnd C1 C1 C2 C2 C3 C3

Sensor Wiring SDM-INT8 CH1 Black - WS #1 CH2 Black - WS #2 CH3 Black - WS #3 CH4 Black - WS #4 CH5 Black - WS #5 All white and clear wires are connected to ground. Note: Set/check the SDM Address on this module.

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Declare Public Variables Public Int8(5) Public PulseCh(2) Dim I Define Data Tables DataTable (Dat5min,1,-1) DataInterval (0,5,Min,10) average (5,Int8(),FP2,False) EndTable Main Program BeginProg Scan (5,Sec,0,0) measure 03101 on P1 & P2 WS_ms: PulseCount (PulseCh(1),1,1,1,1.75,.2) PulseCount (PulseCh(2),1,2,1,1.75,.2) measure 03101 on SDMINT8 channel 1 through channel 5 SDMINT8 (Int8(),3,0002,2222,0002,2222,0,1,1.75,.2) For I = 1 to 5 If Int8(I)<0.21 Then Int8(I)=0 next I Call Data Tables and Store Data CallTable Dat5min NextScan EndProg

7.2 Edlog Program Examples 7.2.1 Cold Crank Engine Test - Capture All Events

The SDM-INT8 is used to obtain timing information during 20 crank cycles or 10 seconds of a 4-cylinder engine cold start test. A crank shaft reference pulse is wired into channel 1. Pulses from the flywheel enter channel 2 so that the counts on 2 since 1 function can be used to measure crank angle. The 4 spark plug firings are picked off a distributor wire and fed into channel 3. Channels 4 and 5 hook onto a fuel injector pulse for measurement of fuel injection pulse width.

The inputs into channels 1 - 5 are as follows:

Channel 1 - crank shaft reference pulse, rising edge Channel 2 - pulse per flywheel tooth, rising edge Channel 3 - pulses from the four spark plugs, rising edge Signals common to single distributor pick-up wire Channel 4 - fuel injector "on" pulse, rising edge Channel 5 - fuel injector "on" pulse, falling edge

The channel functions are programmed as follows:

Channel 1 - Frequency, to get RPM Channel 3 - Counts on 2 since 1, to get crank angle of the spark plug firings Channel 5 - Time since previous channel to get pulse widths of the fuel

injector.

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Parameter 6 (Capture All Events) is programmed for 20--to capture edge times on channels 1-5 until 20 edges are received on channel 1.

Flag 2 is used in the example to indicate the start of the cranking. In actual test program, this flag could be set in response to an ignition switch measurement indicating the start of the test.

When the ignition is turned on (Flag 2 set), Instruction 101 is called, and the SDM-INT8 is programmed. A "loop with delay" is entered to delay for 10 seconds. The Output Flag is set high before executing Instruction 101 again to retrieve the test data.

Three arrays with the following Output array IDs are transferred to the datalogger's Final Storage.:

105 - Stored are hour:minute, seconds, channel 1 frequencies (kHz). 106 - Stored are crank angle results (teeth on flywheel). 107 - Stored are fuel injector pulse widths (ms).

Array 105 - Each time the crankshaft reference is reached, a pulse is generated on channel 1. SDM-INT8 measurements are started by the initial (trigger) pulse on channel 1. The pulse frequency (kHz) will be stored on each subsequent pulse on channel 1 (one pulse per revolution). The pulse frequency can be converted to RPM by multiplying by 60,000. This conversion must be done in the computer, after the test.

Array 106 - Channel 2 receives one pulse each time a flywheel tooth passes a fixed reference point. When a crank shaft reference pulse occurs (channel 1), the crankshaft is in a known position. Each time a spark plug fires, a pulse occurs on channel 3. The output for channel 3 is the number of pulses that have occurred on channel 2 since a pulse from the crank shaft reference (channel 1). A value (number of pulses) will be output for each cylinder in their respective firing order. Every fourth data value in Array 106 will correspond to the same cylinder. The crank angle at each firing can be calculated by multiplying the number of teeth since the crankshaft reference pulse by 360/N, where N is the total number of teeth on the flywheel and subtracting this quantity from 360.

Array 107 - Channel 4 senses a rising edge when the fuel injector is activated. Channel 5 senses a falling edge when the fuel injector is deactivated. The SDM-INT8 calculates the time (ms) between these two edges, thereby calculating the pulse width, or the length of time the fuel injector is on for each pulse.

*Table 1 Programs 01: .5 Sec. Execution interval 1: If Flag (P91) If ignition is 1: 22 2 is reset (Ignition not on) on, execute 02: 0 Go to end of Program Table following 2: Do (P86) address/prgm SDM-INT8 1: 1 Call Subroutine 1 3: Beginning of Loop (P87) loop to make a 10 sec. 1: 1 Delay delay 2: 20 Loop Count

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4: End (P95) end of loop 5: Do (P86) set the output 1: 10 Set high Flag 0 (output) flag 6: Real Time (P77) time tag the output 1: 11 Hour-Minute, Seconds 7: Do (P86) retrieve SDM-INT8 data 1: 1 Call Subroutine 1 8: Do (P86) initialize flag 2 1: 22 Set low Flag 2 9: End Table 1 (P) *Table 3 Subroutines 1: Beginning of Subroutine (P85) 1: 1 Subroutine Number 2: SMD-INT8 (Extended) (P101) 1: 0 Address Option 2: 0001 Chan8765=HLrise/HLrise/HLrise/HLfall/ 3: 0000 Chan4321=HLrise/HLrise/HLrise/HLrise/ 4: 0003 Chan8765=none/none/none/TsinceP/ 5: 0502 Chan4321=none/C2sincel/none/kHz/ 6: 20-- Edges of Chan 1 in events mode 7: 1 Loc: <--- Ignored in "Events" Option 8: 1 Mult 9: 0 Offset 3: End (P95)

7.2.2 Wind Speed Measurements - Execution Interval Averaging The SDM-INT8 is used to make 1 second averages of frequencies from 6 RM Young Wind Monitors. Frequencies are converted to wind speed in m/s, and place in Input Locations 1 - 6. Wind directions are then measured, scaled, and placed in Input Locations 7-12. Programming does not output the data to the dataloggers' Final Storage.

Note that wind speeds of less than 0.2 m/s, corresponding to 2 Hz, will read 0 if a cycle of the Wind Monitor does not get completed within the 1 second execution interval.

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*Table 1 Programs 01: 1 Sec. Execution interval 1: SDM-INT8 (P101) measure wind speed 1: 00 Address Option 2: 0022 Chan8765=HLrise/HLrise/LLrise/LLrise/ 3: 2222 Chan4321=LLrise/LLrise/LLrise/LLrise 4: 0022 Chan8765=none/none/kHz/kHz/ 5: 2222 Chan4321=kHz/kHz/kHz/kHz/ 6: 0 Execution interval averaging (1 second) 7: 1 Loc [:m/s ] 8: 98.0 Mult m/s (convert from kHz to m/s) 9: 0 Offset 2: Excite,Delay,Volt(SE) (P4) measure wind direction 1: 6 Reps 2: 15 2500 mV fast Range 3: 1 IN Chan 4: 1 Excite all reps w/EXchan 1 5: 0 Delay (units .01sec) 6: 2500 mV Excitation 7: 7 Loc [:degrees ] 8: .1420 Mult degrees 9: 0 Offset

7.2.3 Brake Pressure and Wheel Speed Test - Capture All Events and P23 Burst Mode

A CR10X controls an SDM-INT8 to capture about 2 seconds worth of wheel speeds while measuring corresponding brake pressures in Burst Mode. The CR10X's Burst Mode (P23) triggers the SDM-INT8 with Control Port 1 (C1) when the first analog channel measures pressure over the trigger level.

Flag 1 is manually set by the operator to control when the program is entered. After each test, the program sets Flag 1 low to return control to the operator.

The first time through the table, the SDM-INT8 is programmed and starts measuring, looking for the edge on channel 1 that the Burst Mode Instruction (P23) will trigger using C1.

The real time of the brake event (immediately after it occurred) is stored in array ID 9 with P77, followed by the analog burst data in arrays 1,2,3,4 and the timing data from the SDM-INT8 (picked up each time on the subsequent time through the table) in arrays 5,6,7,8.

The Burst Mode measures for 2 seconds (200 scans at 10 ms/scan). The SDM- INT8 measures for about the same 2 seconds, as defined by the trigger edge on channel 1 caused by the start of Burst Mode and the ending edge caused by pulsing Port 1 after the Burst Mode. Data from the SDM-INT8 is stored in Final Storage the next time the table is executed, and the SDM-INT8 is reinitialized for the next brake event.

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*Table 1 Programs 01: .125 Sec. Execution interval 1: If Flag/Port (P91) 1: 21 Do if flag 1 is low 2: 0 Go to end of Program Table 2: Do (P86) 1: 10 Set high Flag 0 (output) 3: Set Active Storage Area (P80) 1: 1 Final Storage Area 1 2: 5 Array ID or location 4: SDM-INT8 (P101) 1: 00 Address Option 2: 0000 Chan4321=HLrise/ HLfall/HLrise/HLrise/ 4: 0002 Chan8765=none/none/none/kHz/ 5: 2220 Chan4321=kHz/kHz/kHz/none/ 6: 1-- Edges of Chan 1 in events mode 7: 1 Loc : (ignored in events mode) 8: 1 Mult 9: 0 Offset 5: Burst Measurement (P23) 1: 4 Reps 2: 12 7.5 mV fast Range 3: 1 IN Chan 4: 2100 TrigINchanSetC1/AboveLim/INpStr/Diff 5: 10 Time per (ms.) 6: .2 Scans ( in thousands ) 7: 0 Samples before Trigger 8: 10 mV Limit 9: 0 mV Excitation 10: 1 Loc : 11: 1 Mult 12: 0 Offset 6: Do (P86) 1: 71 Pulse Port 1 7: Do (P86) 1: 10 Set high Flag 0 ( output ) 8: Set Active Storage Area (P80) 1: 1 Final Storage Area 1 2: 9 Array ID or location 9: Real Time (P77) 1: 11 Hour-Minute,Seconds 10: Do (P86) 1: 10 Set high Flag 0 ( output )

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11: Set Active Storage Area (P80) 1: 1 Final Storage Area 1 2: 1 Array ID or location 12: Sample (P70) 1: 200 Reps 2: 1 Loc 13: Do (P86) 1: 10 Set high Flag 0 (output) 14: Set Active Storage Area (P80) 1: 1 Final Storage Area 1 2: 2 Array ID or location 15: Sample (P70) 1: 200 Reps 2: 201 Loc 16: Do (P86) 1: 10 Set high Flag 0 (output) 17: Set Active Storage Area (P80) 1: 1 Final Storage Area 1 2: 3 Array ID location 18: Sample (P70) 1: 200 Reps 2: 401 Loc 19: Do P86 1: 10 Set high Flag 0 (output) 20: Set Active Storage Area (P80) 1: 1 Final Storage Area 2: 4 Array ID or location 21: Sample (P70) 1: 200 Reps 2: 601 Loc 22: Do (P86) 1: 21 Set low Flag 1 23: End of Table 1 (P) *Mode 10 Memory Allocation 01: 805 Input Locations 02: 64 Intermediate Locations 03: 0.0000 Final Storage Area 2

A-1

Appendix A. Address Jumper The address is factory set at address 00. FIGURE A-1 (also shown inside the SDM-INT8 cover) shows the 15 possible positions and their corresponding address. Use the addresses shown in FIGURE A-1 in Instruction 101.

The address block requires soldering to change the address. If two or more SDM-INT8s are to be used on the same datalogger, one can remain at address 00, while the others must be changed. Disconnect power before opening the case and soldering.

Every SDM device connected to the datalogger must have a unique address.

FIGURE A-1. Address Selection

B-1

Appendix B. Processing Time Limitations

With the exception of the Capture All Events Option or when all channels are programmed for low resolution frequency (Function 6), the SDM-INT8 is performing two tasks simultaneously: (1) measuring and storing, and (2) doing the processing necessary for the final calculations of averages. The time required for processing varies depending on the total number of channels that are used, the total number of edges that occur during the averaging interval, and the function that each channel is programmed for.

With relatively high frequencies and particularly with the more involved processing of the Counts on 2 Since 1 Function, the processing task can lag behind the measuring and storing of the raw edge times. When averaging over the execution interval or when doing continuous averaging (Output Options 0 and 0--) this can shorten the actual averaging window. When averaging over a specified interval (Output Option XXXX) it can lengthen the execution time of the SDM-INT8 instruction. The following formulas are used to calculate the Total processing time (Tt).

Tt = To + Ti

To = Sampling Interval Overhead, ms = 0.511*S +Et*(.034+.010*N)

Ti = processing Time for Function i, ms

T1 = 0.015*E1 T2 = 0.015*E2 T3 = 0.10*E3 T4 = 0.086*E4 T5 = 3.320*E5 +.116*Ec2 T6 = 0.015*E6 T7 = 0.015*E7 T8 = 0.1*E8 + .116*Ec2

where: N = Number of channels measured. Ei = Total number of edges occurring during the interval on those

channels programmed with Function i (i = 1...8). Et = Total number of edges during the interval on all channels. Ec2 = Edges occurring during the interval on channel 2. S = The sampling interval in ms over which the SDM-INT8 samples

the channels.

If the Tt for Output Options 0 and 0-- is greater than the sampling interval, the communication time with the SDM-INT8 will be extended from the minimum time (2.3 ms +1.65 ms/value) only by the processing time needed to obtain an

Appendix B. Processing Time Limitations

B-2

answer for each channel, i.e., till at least one measurement is obtained. These Options should have data ready immediately except in the case of a very slow signal mixed in with relatively fast signals.

If the Tt for Output Option XXXX is greater than the specified interval, the extra time will be added to the execution time of Instruction 101.

Example 1 Given: Output Option = XXXX Specified interval = S = 500 ms Function = frequency (Function 2) Number of channels measured = N = 6 Average input frequency = F = 1kHz

Find: Total Processing Time, Tt

Solution: Tt = To+Ti = To+T2 = 0.511*S+Et*(.034+.010*N) +0.015*E2 = 583 ms

S = 500 ms N = 6 Et = N * S * F = 3000 E2 = Et = 3000

In this case 83 ms is added to the execution time of Instruction 101.

Example 2 Given: N = number of channels measured F = Frequency of input signal, kHz Function = frequency (Function 2) Output Option = 0 or 0--

Find: Maximum average frequency, F, at which the processing time is the measuring/storing time.

Solution:

Tt must be to S; To+T2S

0.511*S +Et*(.034+.010*N) + 0.015*E2 S

Note: Et = E2 = N*F*S

0.511*S+N*F*S*(.034+.010*N)+ 0.015*N*F*SS

F<.489/(N*(.049+.01*N))

Appendix B. Processing Time Limitations

B-3

Results for the above example using all Functions is presented in TABLE 6-2, Sampling Interval (Seconds) to Accumulate 8000 Unprocessed Events for Functions 1,2,6,7 (p. 15).

Example 3 Given: N = number of channels measured F = Frequency of input signal, kHz Function = frequency (Function 2) Output Option = XXXX with specified sampling interval, S

Find: Sampling interval, S, such that the number of unprocessed events is 8000

Solution: The interval required to process 8000 events after the sampling interval is Tt-S, therefore;

(Tt-S)*F*N8000

STt-(8000/(F*N))

S(0.511*S+Et*(.034+.010*N)+0.015*E2) -(8000/(F*N))

Note: E2 = Et = N*F*S

S8000/[F*N((0.511+N*F*(0.49 +.01*N))-1)]

Results for the above example are presented in TABLE 6-2, Sampling Interval (Seconds) to Accumulate 8000 Unprocessed Events for Functions 1,2,6,7 (p. 15).

Appendix B. Processing Time Limitations

B-4

C-1

Appendix C. SDM-INT8 Input Schematic

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