I’m facing a problem with Modbus. I’m trying to write 120 holding registers in one request, but for some reason, Ignition seems to split them into 60 two-register requests. The functionality of the device I’m trying to access, requires a 120-register bulk write.
How do I make the bulk write work?
If absolutely necessary, I could modify the Modbus driver, assuming the SDK has got the current driver, and modifying it would actually help.
- I’m using the “system.opc.writeValues()” script function
- The registers input to the writeValues() function are in an ascending numeric order.
- The device’s been configured as follows:
- Allow Write Multiple Registers Request: ENABLED
- Max Holding Registers Per Request: 125
- Span Gaps: ENABLED
- Force Multiple Register Writes: tried both
- One-based Addressing: DISABLED
- Modbus Driver v2 3.7.5 (b2015071516)
- OPC-UA 2.7.5 (b2015071516)
- Ignition Gateway 7.7.5 (b2015071516)