OMRON C200HW-PRM21 Profibus DP Slave Module for C200H Series PLCs

The OMRON C200HW-PRM21 is a Profibus DP (Decentralized Periphery) slave communication module designed for the C200H, C200HS, and C200HE/HG/HX series programmable logic controllers. This module enables legacy OMRON PLCs to act as a slave device on a Profibus DP network, allowing a Profibus master (such as a Siemens S7-300, S7-400, or any other Profibus master controller) to exchange cyclic I/O data with the OMRON PLC. The C200HW-PRM21 is essential for integrating OMRON controllers into mixed-vendor automation systems, particularly in European factories where Profibus is a widely adopted fieldbus standard.

Technical Specifications

The C200HW-PRM21 supports Profibus DP-V0 (cyclic data exchange) with a maximum of 64 bytes of input data and 64 bytes of output data per scan. The baud rate is automatically detected from 9.6 kbps up to 12 Mbps, making it compatible with all standard Profibus DP networks. The module features a 9-pin D-sub female connector for the Profibus cable, with a built-in switchable termination resistor. The Profibus station address can be set from 1 to 99 using two rotary switches on the front panel. The module occupies one slot in a C200H rack and draws 250 mA from the 5 VDC backplane supply; no external 24 VDC is required.

Data Mapping and PLC Integration

The C200HW-PRM21 maps Profibus input and output data directly to the PLC’s memory areas. Users can configure (via DIP switches or software settings) which PLC memory regions are used: for example, input data received from the Profibus master can be written to the DM (Data Memory) area or IR (Internal Relay) area, while output data to be sent to the master can be read from DM or IR. The module supports both cyclic (synchronous) data exchange for real-time I/O and acyclic parameter data exchange for configuration. The data transfer is transparent to the PLC program; the programmer simply reads from or writes to the assigned memory words as if they were local I/O or special registers.

Configuration and GSD File

To integrate the C200HW-PRM21 into a Profibus network, the user must obtain the GSD file (OMRON_200H.GSD), which describes the module’s capabilities and supported I/O lengths. This file is imported into the Profibus master’s configuration software (e.g., Siemens STEP 7, TIA Portal, CODESYS, or any third‑party Profibus configuration tool). The module appears as a standard Profibus slave with configurable I/O size (up to 64 bytes in and out). The station address is set using the two rotary switches on the front panel: the upper switch for the tens digit, the lower for the units digit. The module also accepts up to 32 bytes of user parameter data, which can be defined in the master’s configuration.

LED Indicators and Diagnostics

The front panel features three LED indicators for quick status checking: “PW” (green) lights when the module is powered; “BF” (red) indicates a bus fault (no communication with the master, incorrect baud rate, or address conflict); “DX” (yellow) lights when data exchange with the master is active. If the BF LED remains on, the user should verify the Profibus cable connections, termination resistors, and station address settings. The module stores diagnostic data (e.g., last error code, communication statistics) that can be read by the Profibus master. For detailed diagnostics, the user can also monitor the special I/O words allocated to the module’s slot in the PLC.

Environmental and Mechanical Data

Operating temperature range: 0°C to 55°C (32°F to 131°F); storage temperature: -20°C to 75°C (-4°F to 167°F). Humidity: 35% to 85% non‑condensing. The module is rated IP20 and is designed for installation inside a C200H series rack. It meets CE, UL, and CSA standards for industrial control equipment and is RoHS compliant. Weight: approximately 0.2 kg. The module is not hot‑swappable; the rack must be powered down before installation or removal.

Typical Applications

The C200HW-PRM21 is typically used when a legacy OMRON C200H PLC must exchange data with a Siemens S7 PLC or a PC‑based Profibus master. For example, in a mixed‑vendor packaging line, a Siemens master might control conveyors and a central SCADA, while an OMRON C200H controls a labeler or a filler. The Profibus link allows the OMRON PLC to send production counts, machine status, and fault codes to the master, and to receive start/stop commands, setpoints, or recipe data. It is also found in automotive body shops, material handling systems, and process control applications where Profibus is the standard fieldbus.

Installation and Setup Procedure

To install the C200HW-PRM21: 1) Power down the C200H rack. 2) Insert the module into any I/O slot except the CPU slot. 3) Connect the Profibus cable to the 9‑pin D‑sub connector. Set the termination switch to “ON” if this module is the last device on the Profibus segment; otherwise set to “OFF”. 4) Set the station address using the rotary switches. 5) Power on the rack. 6) On the Profibus master side, import the GSD file and configure the slave with the correct address and I/O length. 7) Download the configuration to the master. The DX LED should illuminate once data exchange is active. The PLC program can then access the I/O data from the assigned DM or IR words.

Ordering and Legacy Support Information

Order number: C200HW-PRM21. This module is considered obsolete and is no longer manufactured by OMRON. However, it may still be available from aftermarket suppliers or as a refurbished unit. OMRON provides technical documentation (manual W266) for reference, which includes the GSD file and application examples. For new installations, it is recommended to use the CJ1W-PRM21 for CJ series PLCs or to replace the C200H system with a modern CJ2 or NX series PLC. The C200HW-PRM21 supports only Profibus DP‑V0; it does not support DP‑V1 (acyclic parameter access) or DP‑V2.

Important Notes for Network Design

When using the C200HW-PRM21, observe Profibus cabling rules: use standard Profibus cable (purple sheath, characteristic impedance 150 Ω), keep stub lengths as short as possible, and terminate both ends of the segment. The maximum cable length depends on the baud rate: 1200 meters at 9.6 kbps, 100 meters at 12 Mbps. The module does not supply power to the Profibus bus; it is a passive device. Always ensure that the master’s scan time is compatible with the PLC’s cycle time to avoid watchdog timeouts. For further assistance, consult the original OMRON C200HW-PRM21 Operation Manual.