LabVIEW drivers - Watlow Series 96 controller

Watlow Series 96

LabVIEW and the Watlow Series 96 controller use the Modbus RTU protocol to communicate. The driver was developed for a project with 5 controllers on a single RS485 port.

Principle

Since the Watlow controllers uses the Modbus protocol to communicate with, all that needs to be done is to select the right addresses for the parameters of interest. A simple test program can be used to read or write to these addresses. An actual control program might need nothing more than 'read process value' and 'write setpoint'.

The test program can perform the following actions:

• open communication
• read 4 byte data e.g. temperature
• write 4 byte data (signed integer, I32)
• write 2 byte data (unsigned integer, U16)

Downloads

watlow-basic-driver.llb
The included watlow - demo.vi uses the abovementioned read and write functions as well as the 16-bit error checking for the Modbus protocol.