Allen-Bradley 1756-PB72K Power Supply

Configured for power distribution in ControlLogix rack systems, the Allen-Bradley 1756-PB72K (1756-PB72K Power Supply) provides direct physical/electrical execution. This hardware unit accepts an 18-32 VDC input voltage and converts it to regulated backplane power, featuring conformal coating to protect internal circuitry from environmental contaminants within the chassis.

Hardware Specifications

Profinet / EtherNet/IP Deterministic Networks

The 1756-PB72K integrates into the ControlLogix chassis to provide the necessary DC voltage to the backplane bus. Ensuring stable power delivery is a prerequisite for maintaining backplane bus communication velocity across all inserted modules. Users must ensure that the total current draw of the installed I/O and processor modules does not exceed the 2.8 A output capacity of this unit. Proper power budget calculations are necessary, as voltage sag during high-traffic deterministic network operations can lead to intermittent module faults or dropped communication packets.

Frequently Asked Questions

Q: Can the 1756-PB72K be used in a redundant power supply configuration?

A: Yes. Multiple power supplies can be installed in a single ControlLogix chassis to provide redundant power sourcing, provided they are configured according to the chassis backplane power distribution requirements.

Q: Is this power supply compatible with AC input voltages?

A: No. The 1756-PB72K is designed exclusively for a 18-32 VDC input. Connection to an AC power source will result in immediate hardware failure.

Field Installation Guidelines

• Chassis Mounting: Slide the power supply into the designated slot on the left side of the 1756 chassis. Ensure the module is fully seated and the retaining screws are tightened to secure the unit against vibration and ensure proper grounding contact with the chassis frame.
• Input Wiring: Use appropriate gauge wire based on the 18-32 VDC input requirements. Ensure the DC supply source is fused according to local electrical codes to protect the supply input circuitry.
• Environmental Sealing: The conformal coating provides protection against humidity and airborne particles. However, ensure the enclosure remains within specified temperature limits (0-60 deg C) to prevent thermal degradation of the power components.
• Grounding: Connect the chassis ground terminal to a common earth ground. This connection is necessary for both safety and for maintaining signal integrity of the backplane bus.