Hello,

Hold Register can be made with structure of Array of WORD with long enough index value, simply with some reserve to max expected length. In this Register simply set values to each (required for Master) WORD. Master then can read these values as from first to n-th Register. Example can be read from TIA system manual (your version) pdf - check in Search right up input field of this page.

Update: important info for you, you need carefuly check output signals from Comm_Load if it has DONE ok, without errors, also define proper Slave address as Master can correctly poll this Slave address. If this sequence isn't correctly done, your Slave can't work properly.

How do you evaluate the status of system blocks in STEP 7 (TIA Portal)?

hey Ferry1368,

have you seen this FAQ with sample-project:

How do you establish a MODBUS-RTU communication with STEP 7 (TIA Portal) for the SIMATIC S7-1200?

hope this helps,

 regards,