Omron CS1W-SCU31-V1 2-Port RS-422/485 Serial Communication Unit for CS-Series PLCs
The Omron CS1W-SCU31-V1 is a high-performance serial communication unit for the SYSMAC CS-series programmable logic controller systems. This unit provides two RS-422/485 serial ports, enabling the PLC to communicate with a wide range of serial devices such as HMIs, barcode readers, printers, weigh scales, drives, and instruments. The CS1W-SCU31-V1 supports multiple communication protocols including Protocol Macro, Host Link, 1:N NT Link, No Protocol, Serial Gateway, and Modbus RTU Slave, making it a versatile solution for integrating serial devices into the automation system.
Key Specifications
Model: CS1W-SCU31-V1 Serial Communication Unit
Product Series: CS-series Special I/O Unit
Number of Communication Ports: 2 ports
Interface Type: RS-422/485 (selectable per port)
Height: 130 mm
Number of Unit Numbers: 1 unit number allocated
Supported Protocols: Protocol Macro, Host Link, 1:N NT Link, No Protocol, Serial Gateway, Modbus RTU Slave
Serial Gateway Protocols: CompoWay/F, Modbus-RTU, Modbus-ASCII, Host Link
Minimum I/O Response Time: As configured
Logic Type: Programmable via ladder diagram
Mounting: CS-series PLC rack
Ambient Operating Temperature: 0 to 55°C
Standards Compliance: UL, cUL, CE
ETIM Class: PLC communication module
Dual RS-422/485 Port Configuration
The CS1W-SCU31-V1 features two independent RS-422/485 serial communication ports, each configurable for the appropriate interface type and protocol. RS-422 supports point-to-point communication over long distances (up to 1200 meters) with high noise immunity, suitable for connecting devices located in remote areas of the facility. RS-485 supports multi-drop networks, enabling a single port to communicate with up to 32 slave devices on the same serial line. This dual-port configuration allows the PLC to simultaneously communicate with multiple serial devices using different protocols and baud rates.
Protocol Macro Support
The Protocol Macro function is a powerful feature that allows the CS1W-SCU31-V1 to communicate with devices using custom communication protocols. Users can create Protocol Macros that define the sequence of commands, responses, and data handling for specific devices. This capability enables the PLC to interface with serial devices from any manufacturer, even those using proprietary protocols. Once created, Protocol Macros can be executed from the ladder program using simple instructions, simplifying communication programming and reducing development time.
Modbus RTU Slave Capability
The CS1W-SCU31-V1 supports Modbus RTU Slave protocol, making it compatible with the widely adopted Modbus industrial communication standard. When configured as a Modbus slave, other devices (PLCs, HMIs, SCADA systems) can read from and write to the CS-series PLC's memory areas over the serial connection. The Modbus RTU implementation provides reliable communication at standard baud rates, enabling seamless integration with third-party Modbus masters. This compatibility simplifies the incorporation of CS-series PLCs into existing Modbus networks.
Serial Gateway Functionality
The Serial Gateway function allows the CS1W-SCU31-V1 to act as a protocol converter, translating between different communication protocols. The unit supports CompoWay/F, Modbus-RTU, Modbus-ASCII, and Host Link protocols through the Serial Gateway feature. This capability enables devices using one protocol to communicate with devices using another protocol via the communication unit, eliminating the need for external protocol converters. The Serial Gateway function is particularly useful when integrating legacy equipment with modern control systems.
Host Link and 1:N NT Link Protocols
Host Link protocol provides a command-response communication method between the PLC and host computers, allowing external systems to read and write PLC memory areas, monitor I/O status, and control PLC operation. This protocol supports 1:N connections, where a single host computer can communicate with multiple PLCs on the same network using unit numbers for addressing. 1:N NT Link protocol enables connection between the PLC and Omron NT-series operator interfaces, providing economical HMI integration without requiring separate communication modules on the HMI side.
No Protocol Mode for Custom Communication
No Protocol mode allows the CS1W-SCU31-V1 to send and receive raw data without any protocol formatting. In this mode, the user program has complete control over the transmitted data bytes, enabling communication with custom devices or simple ASCII-based equipment such as barcode readers and printers. The ladder program can use specialized instructions to send data buffers and receive data into designated memory areas, with configurable start and end codes. No Protocol mode provides maximum flexibility for unique communication requirements.
Integration with CS-Series PLC Systems
The CS1W-SCU31-V1 mounts directly into the CS-series CPU rack or expansion rack, connecting to the backplane for power and data communication. Input and output data can be allocated freely using the Configurator software, allowing users to customize the I/O assignment for each application. The unit communicates with the CPU through the Special I/O Unit Area, exchanging status information and communication data. The communication parameters and protocol settings are stored in the CPU's DM Area, allowing the unit to be configured without requiring separate programming devices.
Industrial Applications
The Omron CS1W-SCU31-V1 serial communication unit is deployed across a wide range of industrial applications requiring serial device integration. In manufacturing, it connects HMIs, barcode readers, and printers to the PLC for operator interface and data logging. In process control, it interfaces with flow meters, pressure transmitters, and analytical instruments using Modbus RTU protocol. In building automation, it communicates with HVAC controllers, lighting systems, and energy meters. The unit's dual-port configuration allows simultaneous connection of multiple device types, reducing the number of communication modules required.
Conclusion
The Omron CS1W-SCU31-V1 serial communication unit provides dual RS-422/485 ports with support for Protocol Macro, Host Link, Modbus RTU, Serial Gateway, and No Protocol modes for CS-series PLCs. Its flexible protocol support, Serial Gateway functionality, and dual-port configuration make it a versatile solution for integrating a wide range of serial devices into industrial automation systems.
