7. CPU Setup for the Modbus Module
Two lines of ladder logic are necessary to configure a T2 CPU for use with the Modbus module.
1Communications Priority: To insure uninterrupted communications between the CPU and the Modbus module, the communications priority bit S0158 must be set ON.
2.Initialization: To initialize the Modbus module, write the initialization parameter into data register D1470. Register D1470 must be set to H5555 (21845 Decimal) before the Modbus module will start communicating.
When using the Modbus module, the above logic should be placed in Block 1, Rung 1 and Rung 2 of the PLC program.
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