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SDM-INT8  8 Channel Interval Timer 

*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 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 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 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 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 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 INT8 is stored in Final 
Storage the 

next

 time the table is executed, and the INT8 is reinitialized for the 

next brake event. 

24 

Summary of Contents for SDM-INT8

Page 1: ...SDM INT8 8 Channel Interval Timer Revision 4 09 C o p y r i g h t 1 9 8 9 2 0 0 9 C a m p b e l l S c i e n t i f i c I n c...

Page 2: ...s Area 1 in2 square inch 645 mm2 Length 1 in inch 25 4 mm 1 ft foot 304 8 mm 1 yard 0 914 m 1 mile 1 609 km Mass 1 oz ounce 28 35 g 1 lb pound weight 0 454 kg Pressure 1 psi lb in2 68 95 mb Volume 1 U...

Page 3: ...glect accidents of nature or shipping damage This warranty is in lieu of all other warranties expressed or implied including warranties of merchantability or fitness for a particular purpose CSC is no...

Page 4: ...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...

Page 5: ...Edges and Thresholds 2 3 Wiring Diagram 5 4 Example of Multiple Beginnings and Endings 16 A 1 Address Options A 1 List of Tables 1 Bit Period Values 8 2 Instruction 101 10 3 Input Frequency kHz at Whi...

Page 6: ...SDM INT8 8 Channel Interval Timer FIGURE 1 SDM INT8 Front Panel 1...

Page 7: ...m the INT8 through three ports on the datalogger see Section 3 Multiple INT8s each with a unique address may be controlled by one datalogger The INT8 has its own processor which enables it to make mea...

Page 8: ...ising 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 T...

Page 9: ...nnecting the ground lead CAUTION For the 21X a 10K resistor is wired between Control Port 1 and single ended input 1 1H The order in which 21X INT8 connections are made is not critical The CABLE5CBL L...

Page 10: ...selected the INT8 enters the quiescent current drain state 400 microamp current drain after returning the results to the datalogger x If the interval between executions of Instruction 101 exceeds 16...

Page 11: ...ddresses 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 subs...

Page 12: ...en below for each code See Section 6 4 for detailed explanations of each option 0 Stores an average of the event data since the last time that the INT8 was interrogated by the datalogger If no edges w...

Page 13: ...be placed inside a conditional statement when running in pipeline mode NOTE 5 1 2 SDMSpeed Instruction The SDMSpeed instruction is used to change the bit period that the datalogger uses to clock the...

Page 14: ...the first execution of Instruction 101 the INT8 is programmed Subsequent executions of Instruction 101 may command the INT8 to send its processed data to the datalogger or to reinitialize its measure...

Page 15: ...riod 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 cha...

Page 16: ...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...

Page 17: ...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 10...

Page 18: ...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...

Page 19: ...g 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 sign...

Page 20: ...e relationships See Appendix B 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...

Page 21: ...municating 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 INT8 6 4 3...

Page 22: ...aging interval is specified in units of milliseconds The datalogger program is delayed for the specified interval while the INT8 captures edges plus the extra time required for processing if the proce...

Page 23: ...sure without entering the low power mode until 8000 edges are captured Events being measured by the INT8 must not exceed 16 77 seconds or false measurements will be returned The maximum input is 10 kH...

Page 24: ...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 des...

Page 25: ...orage 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 l...

Page 26: ...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 f...

Page 27: ...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 shaf...

Page 28: ...e 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...

Page 29: ...h 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 set...

Page 30: ...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 TrigI...

Page 31: ...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 Fla...

Page 32: ...resses shown in Figure A1 in Instruction 101 The address block requires soldering to change the address If two or more INT8s are to be used on the same datalogger one can remain at address 00 while th...

Page 33: ...This is a blank page...

Page 34: ...rval Output Option XXXX it can lengthen the execution time of the INT8 instruction The following formulas are used to calculate the Total processing time Tt Tt To 6Ti To Sampling Interval Overhead ms...

Page 35: ...1 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...

Page 36: ...ing interval S Find Sampling interval S such that the number of unprocessed events is d 8000 Solution The interval required to process 8000 events after the sampling interval is Tt S therefore Tt S F...

Page 37: ...Appendix B Processing Time Limitations B 4 This is a blank page...

Page 38: ...Appendix C INT8 Input Schematic C 1...

Page 39: ...This is a blank page...

Page 40: ......

Page 41: ...a Corp CSC 11564 149th Street NW Edmonton Alberta T5M 1W7 CANADA www campbellsci ca dataloggers campbellsci ca Campbell Scientific Centro Caribe S A CSCC 300 N Cementerio Edificio Breller Santo Doming...

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