Mounting, wiring, connecting, system interfaces, configuration guidelines 
  12.3 System interfaces 
SIMOCODE pro 
System Manual, 05/2019, A5E40507475002A/RS-AD/004 
251 
 
Figure 12-42  Connecting the 9-pin sub-D connector to the SIMOCODE pro V Modbus RTU basic unit 
 
Figure 12-43  PIN assignments 9-pin sub-D socket 
SIMATIC Industrial Communication 6ES7972* RS485 connectors can be used to connect 
Modbus RTU to the sub-D interface thanks to the identical pin assignments to 
PROFIBUS DP (see RS485 bus connector 
(
https://mall.industry.siemens.com/mall/en/WW/Catalog/Products/9300041?tree=CatalogTre
e) in the Industry Mall). 
 
Using the PROFIBUS DP connector 
When the PROFIBUS DP connector is used, the bus terminator does not conform to the 
Modbus specification. 
Possible functional constraints resulting from the use of the PROFIBUS DP bus terminator 
with a MODBUS TCP are the user's responsibility. 
You can find recommendations for a suitable layout of the serial communication bus in the 
document MODBUS over Serial Line - Specification and Implementation Guide - V1.02 
(http://www.modbus.org/docs/Modbus_over_serial_line_V1_02.pdf
) on the Internet.