Campbell Scientific SDM-INT8 8-Channel Interval Timer - Manual (Page 27)

SDM-INT8 8 Channel Interval Timer
‘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 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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