SST Universal Modbus Modules for CompactLogix Controllers

Molex has introduced two integrated Modbus modules for Rockwell Automation CompactLogix controllers. The modules are claimed to connect CompactLogix controllers to any Modbus/TCP or Modbus serial networks from the same module, even at the same time.

The first module is a Standard version (SST-ERS2-CPX-S) and the second is a Plus version (SST-ESR2-CPX-P), which supports extended addressing to 30,000 I/O words and up to 256 Modbus commands per port. The modules have two independent RS232/RS422/RS485 serial ports that support ASCII and RTU formats. The ports can be configured to operate as Modbus masters and/or Modbus slaves. The software automatically determines if the Modbus message is RS232/RS422/RS485, eliminating the problem of improperly setting dip-switches. Also, each module has one Ethernet port that executes Modbus TCP protocol.

Alternatively, with these modules the Ethernet port can be used as another means for configuration and troubleshooting. This is said to provide additional flexibility for configuration as well as troubleshooting, allowing options for using either a backplane connection or the front of the module. With 2500V electrical isolation between all three Modbus ports, as well as between the ports and backplane, the modules are claimed to provide superior network reliability and smart functionality.

The Molex SST CompactLogix modules can be used in industrial applications, such as water/wastewater, oil and gas, and chemical/petrochemical.