The Allen-Bradley 1771-QA is a Stepper Positioning Assembly. The 1771-QA needs to be paired a 1771-M1, which is a stepper controller module. It includes a 1771-OJ which is a Pulse Output Expander module with a 1771-WB field wiring arm. It supports several of motion applications by programming movements into a single move or a combination of moves such as Acceleration, Deceleration, Constant Velocities, and Final Positions. Each 1771-QA module can control up to 3 pulse output expander modules. Each 1771-OJ operates 1 motor axis. This allows the 1771-QA to expand from 1 to 3 axes per I/O by putting 1 to 3 1771-OJ modules on the chassis. You can add more axes to the 1771-QA stepper positioning assembly with extra I/O chassis. Using the remote I/O, the stepper positioning assembly can redistribute energy throughout the plant. In each axis, the motion can be modified using a pushbutton, thumbwheel switches, or a PC processor. Any Allen-Bradley programmable controllers with block transfer instructions are compatible with the 1771-QA. It has a motion control that features the following function: an E-STOP switch to stop one or all three axes to skip a single move or combination of moves. It can select a single-step, continuous, independent, or a synchronous operating mode. The 1771-QA offers a 999,999-pulse limit range travel extension. It features a starting position to jog reverse or jog forward and it can override moves that are in progress and preset the starting position to any desired value. 

On each I/O chassis, install only one stepper controller and three expander modules. Controllers and modules can fit into any slot on the chassis except for the left-most slot. Use the proper keying position with help from the keying bands to avoid connecting the wrong type of module. The stepper module corresponds to pins 2 to 4 and 8 to 10. The pulse output expander module corresponds to pins 8 to 10 and 22 to 24. Place a 40-foot cable allowance between the expander module and the stepper translator. A twisted 3-conductor shielded cable should be wired by the stepper translator to the wiring arm. This is to avoid electrical noise from affecting the position pulses output by the translator. The temperature range for both modules is 325-1405 °F operating. The 1771-QA has a -405-1855° F storage temperature with a 5-95% humidity rating at no condensation.