Allen-Bradley 1771-IGD TTL Input Module for PLC-5 Systems

The Allen-Bradley 1771-IGD is a 16-point TTL (Transistor-Transistor Logic) input module designed for integration with PLC-5 systems. It facilitates the reception of low-voltage digital signals from field devices, ensuring efficient data processing and control within industrial automation environments.

Key Features

• Input Channels: 16 TTL-compatible inputs
• Operating Voltage: 5.0 to 5.3 V DC
• Logic Level Selection: Configurable for positive or negative logic via an onboard jumper
• Signal Delay: Less than 1 millisecond, ensuring prompt response to input changes
• Backplane Current: 130 mA at 5 V DC
• Power Dissipation: Ranges from 0.4 W (minimum) to 2.7 W (maximum)
• Thermal Dissipation: Between 1.4 BTU/hr and 9.2 BTU/hr
• Operating Temperature: 0°C to 60°C (32°F to 140°F)

Electrical Specifications

The 1771-IGD module supports both positive and negative logic configurations:

• Positive Logic:
  • ON state: 2.0 to 5.25 V DC
  • OFF state: -0.2 to 0.8 V DC
• Negative Logic:
  • ON state: -0.2 to 0.8 V DC
  • OFF state: 2.0 to 5.25 V DC

These configurations allow for flexible integration with various TTL devices, accommodating different signal logic requirements.

Compatibility and Installation

The 1771-IGD module is compatible with the following chassis:

• 1771-A1B
• 1771-A2B
• 1771-A3B
• 1771-A3B1
• 1771-A4B
• 1771-AM1
• 1771-AM2

For proper installation, the module requires the 1771-WH wiring arm, which facilitates secure and efficient wiring connections. The recommended wire size is 14 AWG stranded copper wire with insulation rated for 60°C and a maximum insulation thickness of 1.2 mm.

Indicators and Diagnostics

The front panel of the 1771-IGD module features LED indicators to assist with diagnostics:

• One green “ACTIVE” LED indicating the module is powered and operational
• One green “LOGIC” LED showing the selected logic configuration
• Sixteen red LEDs corresponding to each input channel, displaying the ON/OFF status of individual inputs

These indicators provide real-time status updates, aiding in troubleshooting and system monitoring.

Applications

The 1771-IGD module is ideal for applications requiring the monitoring of low-voltage digital signals, such as interfacing with TTL-level sensors, switches, and other field devices. Its rapid response time and configurable logic levels make it suitable for diverse industrial automation tasks.

By integrating the Allen-Bradley 1771-IGD TTL Input Module into your PLC-5 system, you can achieve reliable and efficient processing of TTL input signals, enhancing the overall performance and responsiveness of your automation setup.