hdhosseini

St33l

Hello. Who could explain me, what functions should I use to organise data exchange between CP341 and Modbus RTU Slave device? In standart system blocks I have found Modbus_Comm_Load and Modbus_Master blocks. Can I use it? I'm asking because in examples from Siemens they don't use this functions. And if I can use this functions, should I buy license for CP341?

Hello,

I think the following discussion with illustrative steps can help you with MODBUS RTU configuration in TIA Portal:

Problem installing cp ptp

plus examples here for TIA Platform:

Sample program MODBUS Master (standard block)

Sample program MODBUS Slave (standard block)

This sample program, contained in the project zXX21_05_PtP_Com_MODSL, includes the standard functions for operating the communications processors CP341 and CP441-2 (as MODBUS Slave).

Software requirements
STEP 7 Professional (TIA Portal) V11.0 + SP 2 and higher

and more information for loadable drivers available for CP341 for MODBUS RTU communication:

Which drivers can be loaded for the serial communication processors?

Hamid Hosseini

 Hi i am also having some problems configuring this module.

This is the firs time I work with modbus on Siemens... 

I have a CPU 315-2 PN/DP PLC and CP 341 RS422/485_1 with modbus master license instald on it, and 2 32 24 DI and 2 32 DO modules.

I hava to use Modbus RTU RS 485

I cannot seem to communicate with my Modbus slave devices.... can someone help me with the configuration. Thank you !

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Split from TIA Portal V13 + CP341 + Modbus RTU.

Hello,

for first you need set proper cfg in CP341 module, depended to your needed protocol. In case of use as Modbus RTU Master select this option in protocol. Next you need set same communication cfg as is defined on Slave, or change in both devices to same if you need other values. You need use RK instructions, in this case look to TIA help with instructions, CP341 manual or Modbus RTU system manual, there you can see also deep description of parameters, status values.

You can look to this topic, is depended to Step7 v5.x but can be useful for you:

Modbus master on 6ES7-341-1CH02-0AE0 stops working

Hi thank you for the response.

I managed to config. the CP module, but I can't seem to communicate with my slaves... 

I do not understand how the RK instructions work

 Also i did not mention that I use tia portal v13

Hello,

yes, you didn't mention nothing, also probably didn't look to name of this topic that talk about TIA v13 solution. I don't have crystal ball my friend. As you can read that linked topic, all is also described in that sugested manuals. There you can see how that instructions work, what you need set for proper functionality. I recommend to you create your own topic next time, not enter topic created by another user, also as i said, reading names of topics is needed. Other questions?

Update: look, investigate, make tests and then ask for other questions, this is good way to learn something...

Hi

Well actually the topic name was why i posted.

As for the update i did all that, but no result....

Sorry if i upset  you, that was not the intention. 

Hello,

so you're use TIA portal v13?  No problem with that, no upset in my side. Info how you're doing that communication will be useful for investigating. Maybe other guys here also can give their sugestions if we see your code pieces. What version of MB driver?

I can only share the document and an MB Pool Document as per equipment. It is relatively simple to access the information in it, I managed to communicate with another PLC (not SIEMENS).

MB driver S7WFPA1X V2.6

code pieces... well there is nothing now. I tried to use Modbus_comm_Load and Modbus_master, I configured them as in the HELP but... no exchange...

That is my problem that i do not know how to configure the CP module, and now to request R/W form the slaves.....

Hello,

look, you must use RK instructions, not MB_COMM and MB_MASTER instructions. They are available to you in library but are for S7-1200 and 1500 CPUs. Use RK instructions under Communication processor->PtP Link CP341. Did you look for that my sugested documents? Also some documents are on CD with CP341 and MB dongle. You need only use that 2 instructions, prepare all needed things and make tests, then give us result, other questions.

Update: only question, how did you solve MB communication on other system? was prepared library or?