Hi,
I am trying to pull values from this Allen Bradley Micro 820 into a test project for Ignition Edge.
I have tested separately A INT value and BOOL value successfully, and read the correct value.
But I am having trouble pulling the correct value for DINT and REAL tags.
The Green highlights are the INT and BOOL Ive been testing,
Yellow are the REAL / FLOAT and DINT that I have not able to pull the correct value.
For "ModbusTest" on the PLC I am sending value "10" and reading "655360"
For "ConductVal" on the PLC I am sending value "4.5" and reading "2.316E-41"
Any suggestions on what I am missing? tried different address setups with no success.
First, abandon the address mappings. Only necessary for browsing with the native driver.
Instead, create Ignition tags with manually-constructed OPC Item Paths, following this documentation:
https://docs.inductiveautomation.com/display/DOC81/Modbus+Addressing#ModbusAddressing-ManuallyCreateanAddressforaSingleTag
Note the use of HRI instead of HR to get 32-bit handling at a given starting address. Similar for other conversion types.
If you need a node address other than zero, it goes before that type prefix, with a dot delimiter.
If you encounter other strange behaviors (off-by-one addresses, scrambled conversions, odd errors when multiple tags are subscribed), examine the device's connection options, particularly:
- Word swapping
- Zero-based addressing
- Spanning gaps
- Maximum request sizes
https://docs.inductiveautomation.com/display/DOC81/Connecting+to+Modbus+Device#ConnectingtoModbusDevice-DeviceConnectionSettings
1 Like
I got it to work with the manually constructed OPC Item paths.. thank you.
Also, be on the lookout for a native driver for these PLCs coming soon (at least Beta is coming soon). This should simplify things hopefully in time for your project since you're just testing it out for now.
any examples of your mappings?
