OVERVIEW

Official designation: Omron CJ1W-DRM21 (CJ Series, DeviceNet Unit)

Role/Application: A CPU Bus Unit for CJ-series PLCs, functioning as both a DeviceNet Master and a Slave to manage distributed control and facilitate data exchange across the network.

KEY SPECS SUMMARY

Power: 5 VDC, 290 mA internal; 24 VDC, 18 mA communications

Interfaces / Ports: Open plug connector

Indicators: Module status, Network status

Operating Temp: 0 to 55 degrees C

Platform / Compatibility: CJ I/O Bus, DeviceNet protocol

Limit: 64 nodes max (total); 63 slaves max (master mode)

Lifecycle: Refer to the latest manufacturer manual.

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What are the three selectable baud rates supported by the CJ1W-DRM21 DeviceNet unit?

A: The unit supports selectable baud rates of 500 Kbps, 250 Kbps, or 125 Kbps.

Wiring & Installation:

Q: What are the specific power and cabling requirements for the DeviceNet network trunk line?

A: The network requires an external 24 VDC communications power supply and proper terminators at both trunk line ends.

Troubleshooting & Compatibility:

Q: What does a red flashing Network Status (NS) indicator on the unit commonly signify?

A: A red flashing NS indicator typically signifies an error in the device's communication configuration, such as a baud rate mismatch.

Replacement & Upgrades:

Q: Can the CJ1W-DRM21 achieve a large number of I/O points when used as a DeviceNet master?

A: When used as a master, the unit supports a maximum of 2,048 fixed allocated I/O points, or more with user-set allocations.