S7-1500 Modbus TCP Client: easy or hard ?

I have a project where I'm scoping out the functions but won't be doing the actual program, so I'm trying to keep everything easy for the person who does.

I see that there's a Modbus/TCP library for S7-1200 and S7-1500, and it looks pretty straightforward. I've done Modbus/TCP on the ControlLogix and it was much more difficult.

The server device is an Acromag I/O block. Nothing time-sensitive.

https://support.industry.siemens.co...ation-between-s7-1500-cpus-and-s7-1200-cpus-?


So my general questions for folks who have done this are:

1. Do you have to buy or license that library block ?
2. Does the ET200SP version of the S7-1500 (the 1510 CPU) support these function blocks ?
3. Is it really as easy as it looks ?

I've used this several times now, it doesn't need any extra license.
The only thing of which you have to take care of, is that you need to recalculate the register addresses depending on the function code you want to use, and how high the register number is.
For example, I wanted to read holding register with address 19000, then I had to use something like 4019001 as register address. Is documented in the help, but it's not obvious.
And if you want to use different unit-ids (for Modbus TCP/RTU gateways for example), you have to write into to the instace datablock as it's for whatever reason not in the interface.