Dear Experts,

I am very new to the Siemens PLC systems. We recently bought S7-300(6ES7315-2EH14-0AB0) , We are having 3rd Party device which supports Modbus and Modbus TCP/IP with ethernet as a Physical Layer and RS-232
How can I make those to communicate with S7-300 for reading data from them?

From some sources I found S7-OPEN MODBUS /TCP FOR PN-CPU software works for my case.
Can any one suggest Me the best possible way of approach.

Thanks In Advance

hii,

if you're using s7300 then u need the s7 open modbus software to be able to communicate with modbus device.

or you can have an profinet/modbus gateway

or you can use s71200 without additional software

br

rusli

Hi rusli,

Thanks for your reply,

Is it open Modbus or open Modbus TCP Software?  

Does it works for both Modbus RTU and Modbus TCP/IP?

If u have any Idea Can u Post its Product Number?

One more Query

One of the 3rd party device comes with RS232, Can I connect it with s7-315 2PN/DP PLC by converting that RS232 to Ethernet? If so How Can I Read that Data?

Thanks!

Hello Saikiran P,

There is a difference between Modbus RTU and Modbus TCP.

Here is some information about Open Modbus:

how do you establich OPEN MODBUS/ TCP communication from a SIMATIC S7 and where can you find futher information?

Modbus TCP can be via integrated PN port (Ethernet)

Modbus RTU can be using a serial communication card. (RS232 or RS485) (CP341) and you need software for Modbus RTU Slave or Master.

Best regards,

Wizard