Allen-Bradley 1769-PB2 CompactLogix Power Supply Module

Configured for auxiliary DC system power generation in CompactLogix and MicroLogix 1500 assemblies, the Allen-Bradley 1769-PB2 (1769-PB2 Power Supply Module) provides direct physical/electrical execution across backplane power distribution rails.

Hardware Specifications

Backplane Bus & Deterministic Network Execution

The expansion power module feeds stable current directly into the internal system chassis, supporting backplane bus communication velocity frameworks across local and distributed I/O banks. Onboard regulated power rails deliver isolated voltage channels that stabilize signal traffic over Profinet / EtherNet/IP deterministic networks, shielding adjacent processor and communication modules from field-side voltage sags. Firmware flash compatibility across system nodes is maintained via continuous reinforced isolation barriers, which absorb supply-line electrical noise during heavy I/O switching cycles. The module architecture facilitates scaling of overall I/O density by supplying up to 8 Compact I/O expansion units on either side of its mounting location.

Frequently Asked Questions

Q: What governs the maximum number of I/O modules that this power supply can drive on a single chassis bank? A: The module carries a power supply distance rating of 8. It can power up to 8 I/O modules installed to its left and 8 I/O modules to its right (maximum 16 modules total), provided the total 5 VDC and 24 VDC bus current drawn by all connected modules does not exceed the unit output current limits.

Q: Can this power supply module be hot-swapped while the 24 VDC field input is energized? A: No, the 1769 Compact I/O system backplane does not support hot-swapping under power. Removing or inserting the power supply module while energized interrupts backplane logic voltages, causing immediate controller communication faults and potential hardware damage.

Field Installation Guidelines

Mount the power supply module directly onto an IEC standard DIN rail or secure it to the enclosure mounting panel using M4 screws. Maintain at least 50 mm (2 in) of vertical clearance above and below the module housing to facilitate natural convection cooling between 0 and 60 deg C.

Wire the 19.2 to 31.2 VDC input power leads to the screw terminals using solid copper wire rated for at least 90 deg C with a gauge of 14 AWG (2.5 mm2) and a maximum insulation thickness of 1.2 mm. Torque terminal block screws to 0.68 N m (6 lb in) to secure electrical conductivity.

Route incoming DC power conductors through dedicated wiring channels separate from low-voltage communication lines and AC motor output leads. Connect the protective earth ground terminal directly to the enclosure main earth ground bar using a low-impedance grounding strap to meet IEC Class 1 grounding requirements.