Modbus TCP Communication Between AS-P and Modicon M221 (TM221CE24R)

[smaghafri95]

Hello everyone,

I’m currently working on a BMS project where an AS-P controller is used to manage lighting  and monitor alarms. For this, I’m using a Modicon M221 (TM221CE24R) with two I/O extension modules:

• TM3DI16 (digital inputs)

• TM3DI32K (digital inputs as well).

This is my first time working with the M221, and I need it to communicate with the AS-P via Modbus TCP so that the AS-P can read the input states and possibly write commands.

Here are my main questions:

1. How do I configure the M221 as a Modbus TCP slave?

2. How can I create and expose Modbus points (coils, registers) in the M221 program so they can be accessed by the AS-P?

3. Is there a default addressing table, or do I need to manually assign each point I want to expose?

Thank you in advance for your support, advice, or any example of a similar configuration!

Best regards,

[Bastian_Schmitz · Accepted solution]

You have to activate manually Modbus TCP Server 

And you have to map all IOs to %MW for 16Bit values (Holding Register) oder %M for (Coil).

Attached a program were I do exactly the same, but I use Modbus RTU instead.