Allen-Bradley 1771-PD Programmable Logic Controller Module

The Allen-Bradley 1771-PD PID Control Module is a two‑loop PID I/O module for the 1771 I/O system, designed to run with PLC‑5 family processors. It occupies two chassis slots, draws about 1.2 A from the backplane, and requires external ±15 V DC power. Each of the two PID loops provides inputs described as two temperature inputs and two tieback inputs, plus two outputs, with 12‑bit resolution and data formatted as scaled BCD ±9999. Analog signals for inputs and outputs are 1–5 V DC or 4–20 mA, enabling direct interfacing to common sensors and transducers. The module interfaces with the processor via standard 1771 backplane connections (including 1771‑WF wiring), delivering closed‑loop control for process variables such as temperature, flow, or pressure in traditional Allen‑Bradley PLC configurations.