Direct Logic DL205 as modbus TCP slave

Has anyone here ever used a Snap controller with automation direct PLC as a modbus slave?
I have a DL205 rack filled with IO cards and I thought it might be easier if I left that rack, threw an ECOM card in and set it up as a modbus slave.

I’ve used Modbus to communicate with AD Click PLCs, it works fine. I don’t think there will be any issues with any of them that speak Modbus.

If you don’t already have it, here is the download link for the Modbus toolkit:

Philip. Thank you. How did you set up the direct logic PLC for this?
I’ve done modbus TCP with snap before but that was in 2008, but that was with some custom german components. I’ve never done it with Direct logic, and their tech support was less than helpful.

I haven’t used a DL205 system, but the manual looks like the modbus addresses can be deciphered pretty easily. You will need to map the value you are looking for to the Modbus Address using the table (copied below for A D2-262) from CH 5 of the ECOM-M manual HX-ECOM-M User Manual for your CPU.

Coils are are Modbus function code 1
Inputs are Modbus function code 2
Holding registers are Modbus function code 3
Input registers are Modbus function code 4

So to read a digital input that is at X0, that would be modbus FC 2 and the address would be 2048. These are zero based, so you want to use register 2049 with the modbus toolkit that Opto22 provides. Though you would normally read a range of values rather than just one at a time.

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