OVERVIEW

Official designation: Allen-Bradley 1791D-4B4P (CompactBlock I/O, Combination Base Module)

Role/Application: A CompactBlock I/O base module with a built-in DeviceNet adapter providing a combination of 4 sinking digital inputs and 4 sourcing digital outputs for distributed control.

KEY SPECS SUMMARY

Power: 11-30V DC DeviceNet power

Interfaces / Ports: 4 sinking inputs, 4 sourcing outputs

Indicators: Mod/Net status (red/green)

Operating Temp: 0 to 60 degrees C

Platform / Compatibility: DeviceNet, PLC, SLC, SoftLogix

Limit: Output current is 0.5A max per point

Lifecycle: Discontinued by manufacturer

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What is the isolation rating between the DeviceNet power, I/O groups, and auxiliary power?

A: Isolation is rated at 500V AC between DeviceNet power, I/O groups, and auxiliary power.

Wiring & Installation:

Q: What field wiring terminal type does the 1791D-4B4P module utilize for inputs and outputs?

A: The module uses removable screw-clamp terminal strips and accepts wiring up to 14 AWG.

Troubleshooting & Compatibility:

Q: What safety function is included to manage outputs if the internal microprocessor fails?

A: A hardware watchdog function is included to put all outputs into a safe, known state if failure occurs.

Replacement & Upgrades:

Q: Does the 1791D-4B4P base module support expansion modules for a higher I/O point count?

A: Yes, this base module can be coupled with one compatible 16-point expansion module.