Entry type: FAQ, Entry ID: 58386780, Entry date: 07/01/2015
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Which hardware and software components do you need to establish communication between SIMATIC S7 stations and third-party devices using the MODBUS RTU protocol?

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This entry gives an overview of the hardware and software components you need to establish communication between SIMATIC S7 stations and third-party devices using the MODBUS RTU protocol.

The SIMATIC S7 stations below can be used as Modbus Master (RTU) and Modbus Slave (RTU):

  • SIMATIC S7-1500, SIMATIC ET 200MP, SIMATIC ET 200SP
  • SIMATIC S7-1200
  • SIMATIC S7-300, ET 200M and S7-400
  • ET 200S
     
SIMATIC S7-1500, SIMATIC ET200MP, SIMATIC ET200SP
The SIMATIC S7-1500 station can be used as Modbus Master (RTU) or Modbus Slave (RTU).

In the S7-1500 you need one of the following communication modules to connect a third-party device and establish communication with the MODBUS RTU protocol.
 

Communication module Article number
CM PtP RS232 HF (for S7-1500 and ET200MP) 6ES7541-1AD00-0AB0
CM PtP RS422/485 HF (for S7-1500 and ET200MP) 6ES7541-1AB00-0AB0
CM PtP (for ET200SP) 6ES7137-6AA00-0BA0

Further Information

  • More information about communication using the MODBUS RTU protocol with the S7-1500, the ET 200MP and the ET 200SP is available in the manual in Entry ID 59057093
  • Entry ID 68202723 includes a sample program for establishing MODBUS-RTU communication for SIMATIC S7-1500.

 

SIMATIC S7-1200
The SIMATIC S7-1200 station can be used as Modbus Master (RTU) or Modbus Slave (RTU).

In the S7-1200 you need one of the following communication modules to connect a third-party device and establish communication with the MODBUS RTU protocol.
   

Communication moduleArticle number
CM 1241 RS422/4856ES7241-1CH32-0XB0
CM 1241 RS422/4856ES7241-1CH31-0XB0
CM 1241 RS4856ES7241-1CH30-0XB0
CB 1241 RS4856ES7241-1CH30-1XB0
CM 1241 RS2326ES7241-1AH32-0XB0
CM 1241 RS2326ES7241-1AH30-0XB0

Further Information

  • More information about communication using the MODBUS RTU protocol is available in the manual in Entry ID: 36932465.
  • A sample program for establishing MODBUS-RTU communication for SIMATIC S7-1200 is available in Entry ID: 47756141.

SIMATIC S7-300, ET 200M or S7-400
SIMATIC S7-300, ET 200M and S7-400 can be used as Modbus Master (RTU) or as Modbus Slave (RTU).

In S7-300, ET 200M and S7-400 you need the hardware and software components below to connect a third-party device and establish communication with the MODBUS RTU protocol:

  • A serial CP
    • CP341 for S7-300 and ET 200M
    • CP441-2 for S7-400
  • The relevant loadable driver

The table below gives an overview of the hardware and software components.
   

Hardware and software componentsNote
CP341 The loadable drivers Modbus Master (RTU) and Modbus Slave (RTU) can be installed on the serial CP341 with the article numbers below:
  • 6ES7341-1AH02-0AE0
  • 6ES7341-1BH02-0AE0
  • 6ES7341-1CH02-0AE0
CP441-2The loadable drivers Modbus Master (RTU) and Modbus Slave (RTU) can be installed on the serial CP441-2 with the article numbers below:
  • 6ES7441-2AA05-0AE0
       

Note
For the CP441-2 you also need the corresponding interface module:

  • 6ES7963-1AA10-0AA0 with RS232 interface
  • 6ES7963-2AA10-0AA0 with TTY interface
  • 6ES7963-3AA10-0AA0 with RS422/RS485 interface
Loadable driver Modbus Master (RTU)The loadable driver Modbus Master (RTU) for CP341 and CP441-2 is available for downloading in Entry ID: 27774018.
The license for the loadable driver Modbus Master (RTU) is available under the article numbers below.
  • 6ES7870-1AA01-0YA0: the license delivery package includes the software, documentation and hardware dongle
  • 6ES7870-1AA01-0YA1: the license delivery package includes only the hardware dongle
Loadable driver Modbus Slave (RTU)The loadable driver Modbus Slave (RTU) for CP341 and CP441-2 is available for downloading in Entry ID: 27774276.
The license for the loadable driver Modbus Slave (RTU) is available under the article numbers below:
  • 6ES7870-1AB01-0YA0: the license delivery package includes the software, documentation and hardware dongle
  • 6ES7870-1AB01-0YA1: the license delivery package includes only the hardware dongle

Further Information

More information about commissioning the loadable drivers Modbus Master (RTU) and Modbus Slave (RTU) is available in the manuals below.
   

Manual

Entry ID
SIMATIC S7-300/S7-400 Loadable Drivers for PtP CPs: MODBUS Protocol RTU Format, S7 is Master

1220184

SIMATIC S7-300/S7-400 Loadable Drivers for PtP CPs: MODBUS Protocol RTU Format, S7 is Slave

1218007

How to download a loadable driver such as Modbus Master (RTU) into a CP341 that is connected to an S7-400 H system by means of an ET 200M is described in Entry ID: 17854293.

SIMATIC ET 200S
The SIMATIC ET 200S can be used as Modbus Master (RTU) or as Modbus Slave (RTU).

In the ET 200S you need a serial interface module ET 200S Modbus/USS to connect a third-party device and establish communication with the MODBUS RTU protocol.
 

Serial interface moduleArticle number
ET 200S 1SI6ES7138-4DF11-0AB0

Further Information
More information about the serial interface module ET 200S Modbus/USS is available in the manual in Entry ID: 9260793.