Hi every body, 

I am working on a project using a Siemens S7-300 CPU (317-2 PN/DP)and anET200S station with a1SI module (6ES7 138-4DF11-0AB0). My goal is to use this 1SI module to read data from Modbus RTU slave sensors (e.g., Energy Metter) via RS-485.

I don't use a CP340 or CP341. The 1SI module is connected to anIM151-1and configured in TIA Portal V16. I want to use the CPU as Modbus RTU Masterand have tried the MB_COMM_LOAD and MB_MASTER blocks from the Siemens Modbus library.

My main questions:

1. Can the 1SI module in ET200S be used as a Modbus RTU Master without CP modules?

2. Are MB_COMM_LOAD and MB_MASTER the correct blocks for this?

3. Is the S_MODB block only for Slave mode?

4. Do you have official documentation or example projects for this setup?

Your clarification would help me complete this critical part of my project.

Best regards,
MR.Ghaemi

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Split from MB_COMM_LOAD and MB_MASTER aren’t supported by ET200S 1SI module.