Allen-Bradley 1771-QB PLC 5 Linear Positioning Module

Overview

The 1771-QB (1771-QB) is a specialized single-slot motion control module designed for the PLC-5® Universal I/O chassis. It provides precision closed-loop linear positioning by interfacing directly with high-accuracy transducers. This module is engineered to handle complex hydraulic or pneumatic servo positioning tasks by calculating position data every 2 milliseconds. By offloading motion intensive calculations from the main processor, the 1771-QB (1771-QB) ensures high-speed response times and deterministic performance for industrial machinery.

Detailed Technical Specifications

• Module Type: Linear Positioning Control

• System Platform: PLC-5 Universal I/O

• Sampling Rate: 2 ms per axis update period

• Backplane Power Consumption: 1.1A typical / 1.6A maximum at 5V DC

• Supported Transducers: MTS Temposonics, Balluff BTL, and Norstat GYRG (Linear Displacement)

• Analog Output Resolution: 12-bit

• Analog Servo Outputs: +/-10V DC (10 mA), +/-20 mA (600 ohms), +/-50 mA (240 ohms), +/-100 mA (240 ohms)

• Discrete Input Logic: 10-30V DC for Logic 1; 0-4V DC for Logic 0

• Discrete Input Current: 8 mA at 12V DC; 16 mA at 24V DC

• Discrete Sourcing Outputs: 100 mA maximum per output (ON state)

• Circuit Protection: 3 Amp, 250V Normal-Blow Fuse

• Required Wiring Arm: 1771-WN or 1771-WNF (40 terminals)

• Maximum Wire Size: 14 AWG stranded with 3/64 inch insulation

• Physical Weight: 6.00 lbs (2.72 kg)

• Chassis Space: 1 Slot

Positioning Capabilities and Connectivity

The 1771-QB (1771-QB) is built for versatility in feedback integration, supporting multiple magnetostrictive transducer brands. It features auxiliary digital inputs and outputs for home indexing, end-of-travel limits, and drive enable signals. The high-resolution 12-bit analog output allows for exceptionally smooth control of servo valves. For remote applications, the module is compatible with the 1771-PSC cable assembly, ensuring signal integrity over a 5.5 ft distance between the module and its interface.

Engineering FAQ

• Which transducers are compatible with the 1771-QB? The 1771-QB (1771-QB) is primarily designed to interface with magnetostrictive linear displacement transducers (LDTs) that utilize specialized pulse-based or start/stop signals, such as those from MTS Temposonics or Balluff.

• Can this module control more than one axis? The 1771-QB (1771-QB) is a single-axis positioning module. For multi-axis synchronized movement, multiple modules must be installed and coordinated via the PLC-5 backplane.

• Is the 1771-QB hot-swappable? While the 1771 chassis is rugged, it is standard engineering practice to remove power from the I/O chassis before replacing the 1771-QB (1771-QB) to prevent damage to the sensitive analog servo outputs.