Hi,

I would like to test my program according this manual:

https://support.industry.siemens.com/cs/document/109474714/master-slave-communication-with-modbus-rtu-protocol-for-s7-300-and-et-200s-systems?dti=0&lc=en-WW

My problem is that from Hardware I have 1 part missing, thats DONGLE for CP341

So I got S7-300 CPU, CP341 (modbus master), ET200S CPU, Modbus rtu 1S module for ET200S .

I'm missing CP 341 dongle.

IS there any way to test my program even in demo mode for 10 mins or something without DONGLE

Hello,

also I want to ask you (as I see your HW cfg), you have S7-300 and ET200s. Your ET200 has MB RTU comm module, this module is connected to CP341 of S7-300? Why this complicated solution? What next interfaces you have available on both systems? Can you confirm that RTU interfaces are for inter connection S7-300 to ET200s? In most cases simply I see simplest solution use Profinet or Profibus or maybe user communication. Can you send better info? What amount of data you need Exchange between both systems?

Duris_I

Hello,

also I want to ask you (as I see your HW cfg), you have S7-300 and ET200s. Your ET200 has MB RTU comm module, this module is connected to CP341 of S7-300? Why this complicated solution? What next interfaces you have available on both systems? Can you confirm that RTU interfaces are for inter connection S7-300 to ET200s? In most cases simply I see simplest solution use Profinet or Profibus or maybe user communication. Can you send better info? What amount of data you need Exchange between both systems?

 Hello Duris_I, and thx a lot for hetting involved in order to help me.

I have two cubicles and  inside each there are 2  CPUs s7-400H

Inside third cubicle is S7-300.

Inside fourth cubicle is ET200s, but fourth cubicle is 5 kilometres away from these 3 cubicle I mentioned before.

SCADA is next to these 3 cubicles. SCada must communicate with 4 devices in some other cubicles which supports RTU RS485.

On the end I have decided to place s7-1200 1212C (6ES7212-1AE40-0XB0) and CM 1241 RS422/485  6ES7241-1CH32-0XB0   into cubicle with with S7-300.

S7-1200 with MODBUS collects data from 4 protection relays SEL-787

PUT/GET  takes data to the S7-300 from S7-1200.

Scada read data from S7-300

Hello,

ok, understand that CP341 acts as MB Slave to Scada? No other way as use dongle in this way or as Daniel sugested with Tibi's solution, but if I'm wrong with my opinion about CP341, be carefuly to select correct Master or Slave RTU.

New question published by Willybong is split to a separate thread with the subject How many stations MODBUS RTU slave could I have?.

Best regards
Jen_Moderator