1. General Information

• Manufacturer: Reliance Electric (Rockwell Automation)

• Part Number: 0-51668-1 (also written as 0516681)

• Product Type: Process Control Interface Board / Module

• Application: AutoMax DCS / DCS 5000 systems, industrial process control

• Function: Provides isolated signal interfacing, analog/digital I/O, and serial communication between the control system and field devices

• Status: Obsolete (discontinued); available as new old stock, used, or refurbished

• Warranty: 12 months (refurbished / new old stock)

• Certifications: CE, UL, CSA

2. Electrical Specifications

• Backplane Power: +5 VDC

• Local Power: 12 VDC

• Power Consumption: Max 5 W

• Communication Ports: RS-232, RS-485

• Relay Outputs: 8 channels SPDT, 2 A per contact

• Signal Isolation: 1500 VAC (field-to-logic)

• Input/Output Type: Supports standard industrial analog and digital signals

• Protection: Overvoltage, surge, reverse polarity

3. Physical & Mechanical

• Dimensions (W × H × D): 244 mm × 155 mm

• Weight: Approx. 0.8 kg (1.02 kg some sources)

• Form Factor: Standard AutoMax rack-mount card

• Connection: Edge connector (backplane), screw terminals (field)

• Construction: Industrial PCB with conformal coating

4. Environmental Ratings

• Operating Temperature: -20°C to +70°C

• Storage Temperature: -25°C to +75°C

• Humidity: 5%–95% RH, non-condensing

• Vibration: Industrial-grade, suitable for control cabinet installation

5. Compatibility

• Systems: Reliance AutoMax DCS, DCS 5000

• Related Modules: 0-51486-17 (analog input), 0-51444 (power supply)

• Drives: Compatible with Reliance AC/DC variable-speed drives

6. Installation Notes

1. Remove rack power before installation.

2. Insert into standard AutoMax rack slot and secure.

3. Connect field signals to screw terminals.

4. Verify +5 VDC backplane and 12 VDC local power.

5. Check communication and relay operation after power-up.