S7 1200 to Sepam MODBUS RTU Addressing

[boneless]

Hi all!

So I got tasked with this fun little project. I have never done anything with MODBUS RTU and am having quite a bit of fun doing this. One little issue I am unsure about.

Schneider is delivering 2 SEPAM units that are supposed to communicate with our 1200 CPU (with CB1241 interface installed).

The Siemens program is set up to communicate with registers 40000 and up, while the IO table I got from Schneider references HEX codes 010B and up.

Am I right to assume that I can just add 010B to my 40000? FE 40267 in that case?

Thanks!

 

[boneless]

We got this working today, clue is just to add 40001 to the addresses provided.

So, for current. HEX 0113 = DEC 275. Is 40276 as input into the Siemens FB.

Whoop!

 

[sigmadelta]

I've found very rarely is there a device manual that spells out its Modbus addressing clearly... there usually is some indirect allusion to some sort of address you have to figure out for yourself...

 

[boneless]

I have to say that the manual is very good actually, the problem is my lack of knowledge .

They way Siemens (seems) to do function codes etc, is by adding a specific range to the address. Hence the 40001 added (function code 03).