GE 90-30 Addressing with Modbus TCP Driver


I am using Ignition V7.8.0 to connect to a GE 90-30 model IC693CPU374 PLC with the Modbus TCP Driver.
I am simply trying to duplicate an existing GE Quick Panel HMI application using Ignition.

I can successfully create tags to address and connect to the following PLC addresses of my device PLC.
Discrete Inputs like %I00420 using OPC Item Path [PLC]DI420
Discrete Outputs like %Q00429 using OPC Item Path [PLC]C429
Real holding registers like %R00082 using OPC Item Path [PLC]HRF82
Integer holding registers like %R00288 using OPC Item Path [PLC]HR288

I can not, however, successfully address and connect to any internal bits like %M00001.
Looking over the documentation, it is not clear if the %M internal bits are even available over the Modbus TCP driver.

Has anyone had success connecting to internal bit (%M) registers of a GE 90-30 PLC with Ignition?
Is there a different driver specifically for the GE 90-30 that I’m missing?
Any suggestions are always appreciated.

Thank you for your help,


GE-9030 PLC support below Modbus addresses
Input status - Discrete Inputs (%I)
Coil Status - Discrete Outputs (%Q)
Holding Registers - Registers (%R,%AO)
Input registers - Input registers (%AI)

For %M,%G, %S you have to map these to %Q or %R memory then only these can be accessible via Modbus.


Thank you for your help!

One followup question if possible.

Is this mapping something that is configured or do you simply use lots of move instructions to move variables back and fourth from %M to %Q?

Thank you again,


Use move instruction for mapping, there is no alternate way for this.

If %M bits are used in byte align fashion then you could move bunch (Words) wise with using minimum move Integer/Word function blocks, otherwise use move bit function.