Campbell Scientific CR9000X Measurement and Control System - Manual (Page 249)

Section 7. Measurement Instructions
7-25
SDMCAN Example 2
The following example uses the request/receive capability of the SDMCan to
request a data frame with an 11 bit identifier in the Slow Sequence Scan.
' /////////////////////// DECLARATIONS \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
'_________________________ Volt Block 1 _________________________
Public VBlk1(1): Units VBlk1 = mVolts
' _____________ CANBUS _________________________/
'Setup SDMCANBus Address and CAN Network Communication Values
Const CanAddress=0 : Const CanQuanta=1 : Const CanSeg1=5 : Const CanSeg2=2
Public CanSwitchTx, CanSwitchRx
'Config values to send (Tx) and confirm (Rx) on SDM-CAN
Public Can001(1) : Units Can001 = kPAbsolute : Alias Can001(1) = P0BIntakeMAP
Public Flag(8)
'General Purpose Flags
' \\\\\\\\\\\\\\\\\\\\\\\\ OUTPUT SECTION ////////////////////////
DataTable(Table1,True,-1) 'Trigger, auto size
DataInterval(0,1,Sec,100) '1 Sec interval, 100 lapses, autosize
Sample (1,VBlk1(),IEEE4) '1 Reps,Source,Res
Sample (1,Can001(),IEEE4) '1 Reps,Source,Res
EndTable 'End of table Table1
'\\\\\\\\\\\\\\\\\\\\\\\\\\\\ PROGRAM ////////////////////////////
BeginProg
'Preliminary CanBUS Configuration Scan(s)
CanSwitchTx=0004 'EnableTransmit, UseOldData
Scan(1,Sec,0,10) 'Set Switches - NAN and TxEnable
'CANBUS ID 1 = Config SDM-CAN, DataType32 = SetSwitch, NumVals = 1
SDMCAN( CanSwitchTx,CanAddress,CanQuanta,CanSeg1,CanSeg2,1,32,0,0,1,1. 0,0.0)
'CANBUS ID 1 = Config SDM-CAN, DataType33 = ReadSwitch, NumVals = 1
SDMCAN (CanSwitchRx,CanAddress,CanQuanta,CanSeg1,CanSeg2,1,33,0,0,1,1.0,0.0)
If CanSwitchRx = CanSwitchTx Then ExitScan ' Exit Scan once setting is verified
NextScan
' \\\\\\\\\\\\\\\\\\\\\ MAIN SCAN ///////////////////////////
Scan(10,mSec,10,0) 'Scan once every 10 mSecs, non-burst
VoltDiff(VBlk1(),1,17,4,1,True,30,100,1,0)
CallTable Table1
Next Scan
'Loop up for the next scan
SlowSequence 'Used for slow measurements
Dim idx 'Index for looping through Rx Retries
Public ByteTx(8),ByteRx(8) 'Intermediate Transmit and Receive placeholders
Do 'For CANBUS TxRx, we need mult, repeating scans
Scan(20,mSec,0,1) ' Back Ground Calibration Scan once during every Do-loop
Calibrate 'Corrects ADC offset and gain
BiasComp 'Corrects ADC bias current
Next Scan 'Loop up for the next scan
'Setup Transmit Data Frame: &H02010B0000000000 for J1979 Legislative PID $0B
'This request is for the Intake manifold absolute pressure.
ByteTx(8)=&H02 : ByteTx(7)=&H01 : ByteTx(6)=&H0B : ByteTx(5)=&H00
ByteTx(4)=&H00 : ByteTx(3)=&H00 : ByteTx(2)=&H00 : ByteTx(1)=&H00
SDMCan (ByteTx(),CanAddress,CanQuanta,CanSeg1,CanSeg2,-&H7DF,19,1,8,8,1,0)
For idx=0 to 50 'Look for the Rx that matches the Tx 50 times
Delay(1,20,mSec) 'Wait for 20msec - timing issue
SDMCan (ByteRx(),CanAddress,CanQuanta,CanSeg1,CanSeg2,-&H7E8,1,1,8,8,1,0)
'Check the Rx value just obtained; if it matches &HXX410BXXXXXXXXXX -decode it
If (ByteRx(6) = &H0B) And (ByteRx(7) = &H41) Then
'DataType=1, StartBit=33, NumberofBits=8, NumberofValues=1, Mult=1, Offset=0
SDMCan (Can001(),CanAddress,CanQuanta,CanSeg1,CanSeg2,-&H7E8,1,33,8,1,1,0)
ExitFor
EndIf
Next idx
'Return for next time through the loop
Loop 'Loop back to the "DO"
EndProg 'Program ends here