Product Summary for the Allen-Bradley 1771-IGD
The Allen-Bradley 1771-IGD is a versatile TTL input module for the PLC-5 family. It delivers sixteen selectable logic inputs within a single slot. This module processes high-speed digital signals with a rapid signal delay of less than one millisecond. Engineers rely on it for precise 5VDC logic state detection in demanding industrial environments.
Expert Technical Evaluation & Performance Review
The 1771-IGD module provides sixteen TTL-compatible input points for your control system. It operates on a customer supply voltage of 5.0 to 5.3 Volts DC. This module requires a Class 2 power supply with a maximum peak-to-peak ripple of just 50 mV. Its backplane current draw measures 130 mA at 5VDC, ensuring efficient power usage.
This module features a key advantage with its selectable logic states. By default, it uses positive logic. In this mode, an ON state requires 2.0 to 5.25 Volts DC, while an OFF state is -0.2 to 0.8 Volts DC. You can reverse this by setting the jumper for negative logic, where ON is -0.2 to 0.8 Volts DC. This flexibility adapts to different sensor and signal types.
The signal processing performance is exceptionally clean and reliable. Input signal delay for the ON state is typically less than 1 ms. The DC signal delay for the OFF state is rated at 20 ms, with a +/- 9 ms tolerance. This module also provides an isolation voltage of 1500V AC RMS for one second. This protects your system from ground loops and voltage spikes.
Power dissipation remains low, ranging from a minimum of 0.4 Watts to a maximum of 2.7 Watts. This keeps your chassis cool, even in dense configurations. The operating temperature range spans from 0 to 60 degrees Celsius. A built-in 0.5 Amp, 250V normal blow fuse protects the input terminal from accidental overvoltage. This safeguard ensures long-term reliability for your critical I/O points.
Step-by-Step User & Installation Guide
Begin by installing the 1771-IGD module into a compatible 1771 chassis. It works with Series A or B models like the 1771-A1B, 1771-A2B, and 1771-A4B. You can also use it in 1771-AM1 or 1771-AM2 I/O chassis. Slide the module firmly into the guided rails until it seats properly. Then, tighten the top and bottom retaining screws to secure it.
For signal wiring, you must use the 1771-WH wiring arm. This arm provides the physical connection point for your field wiring. Use 14 American Wire Gauge (AWG) stranded copper wire for all terminations. Ensure the wire has an insulation rating of 60 degrees Celsius. The maximum insulation thickness should be 3/64 or 1.2 millimeters.
We recommend using Belden 8761 cable or any equivalent cable for signal transmission. When tightening each terminal screw, apply a torque of 9 lb-inch or 1.0 Newton-meter. This ensures a gas-tight connection that resists vibration. Remember to set the logic jumper on the front of the module for your specific application. Use positive logic for standard NPN sensors or negative logic based on your system design.
Mount the 1771-IGD module in a rack-mountable configuration. This placement ensures optimal airflow and easy access for maintenance. The module is an earlier model, but it remains a reliable choice for legacy systems. Always follow standard ESD precautions when handling the module to prevent component damage.
Logistics & Standard Packaging Details
