Omron CJ1W-SRM21 CompoBus/S Master Unit

The Omron CJ1W-SRM21 is a CompoBus/S Master Unit designed for CJ-series PLCs, enabling rapid and decentralized control of remote I/O devices. Supporting up to 256 I/O points and 32 slave nodes, this unit uses Omron’s proprietary CompoBus/S protocol to achieve high-speed I/O refreshing as fast as 0.5 ms, making it ideal for high-throughput machines requiring real-time responsiveness.

With flexible cabling options including flat cable or VCTF, and operation in both high-speed (750 kbps) and long-distance (93.75 kbps) modes, the CJ1W-SRM21 simplifies wiring and enhances layout flexibility—perfect for assembly, packaging, or transfer systems.

Technical Specifications

Model: CJ1WSRM21
Series: CJ1W
Product Type: CompoBus/S Master Unit
Mounting Type: DIN rail via CJ-series rack
Dimensions (W × H × D): Refer to datasheet
Weight (Unpacked): Approx. 100 g
Unit Type: Special I/O Unit
Applicable PLCs: CJ-series PLCs

I/O Capabilities

• Max I/O Points:
  • 256 (128 inputs + 128 outputs)
  • 128 (64 inputs + 64 outputs)
  • Switch-selectable
• Word Allocation:
  • 256 I/O mode: 20 words (8 input, 8 output, 4 status)
  • 128 I/O mode: 10 words (4 input, 4 output, 2 status)
• Mountable Master Units: Up to 40 per CJ system

CompoBus/S Communication

• Protocol: Proprietary CompoBus/S protocol
• Baud Rates:
  • High-speed Mode: 750 kbps
  • Long-distance Mode: 93.75 kbps
• Max Connected Slaves: 32
• Cycle Time: 0.5 ms (typical at max speed)
• Node Addressing: 8 addresses per node
• Status Monitoring: Participation Flags, Communication Error Flags

Communication Cabling Options

• VCTF Cable (2-conductor / 4-conductor)
  • High-speed: Up to 100 m (main), 3 m (branch), 50 m total branch
  • Long-distance: Up to 500 m (main), 6 m (branch), 120 m total branch
• Special Flat Cable (4-conductor)
  • High-speed: Up to 30 m (main), 3 m (branch), or 100 m/50 m with fewer than 16 slaves
  • Long-distance: Flexible up to 200 m total

Communication Details

• Encoding: Manchester
• Modulation: Baseband
• Error Checks:
  • Manchester code verification
  • Frame length check
  • Parity check
• Topology: Bus with free wiring structure (especially in long-distance mode)

Applications

Perfect for:

• High-speed packaging or bottling machines
• Decentralized I/O in conveyor or transfer systems
• Systems requiring short communication cycle times
• OEM applications using Omron’s remote I/O ecosystem
• Machines where simple, branched wiring is preferred

Key Features & Benefits

✅ Up to 256 I/O Points: Scalable control for large remote setups.

✅ Fast I/O Refresh (0.5 ms): For high-speed industrial machine cycles.

✅ Flexible Cabling Options: Supports flat cable and VCTF with multiple layouts.

✅ Simple Network Integration: Connects up to 32 slave nodes with minimal configuration.

✅ Omron Proprietary Reliability: Designed for seamless CJ-series PLC integration.

📦 Available from Drive Outlet Megastore

The Omron CJ1W-SRM21 offers robust, ultra-fast I/O control over flexible network topologies, enabling simplified wiring and rapid control response in demanding automation systems.

Need help designing your CompoBus/S remote I/O network or selecting compatible slave modules?
Talk to our industrial networking team today.

High-speed I/O. Simplified cabling. Drive Outlet brings Omron networks to life.