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LabVIEW drivers - RKC CB500 controller
Communication between LabVIEW and the RKC CB500 controller has proven to be quit a challenge. Difficult as it may seem, the information provided by RKC proofs to be accurate. The protocol uses common ASCII characters like 'EOT', 'ENQ' and 'NAK'. Using these characters it is possible to set up a driver with retry capability.
This driver uses a state-machine, which is a case-statement in which an executed case decides which case will be executed next.
The following cases for reading the process value can be recognized (in rkc read.vi):
This sub-vi supports retries because it can send a 'negative acknowledge' or 'NAK'.
The following cases for writing the setpoint value can be recognized (in rkc write.vi):
This sub-vi does not support retries.
Bart Boshuizen, 2007/07/20