Overview
The Allen-Bradley 1771-IAD/C is a 16-point discrete digital input module engineered for PLC-5 Series C control systems. This module provides 16 input channels that can handle both 120VAC and 125VDC input voltages. Operating voltage range is 79–138V AC and 79–138V DC, making it compatible with a wide range of industrial signal levels. The module interfaces directly with pushbuttons, limit switches, relay contacts, and other discrete on/off sensors.
Key Features
- 16 Discrete Input Channels: Sixteen (16) input channels compatible for 120VAC / 125VDC input voltage
- Signal Isolation: Optoelectrical isolation to protect the system circuits from electrical transients and input filtering feature to reduce electrical noise
- Fast Signal Processing: Input signal delay of 120V ac/60Hz: 5ms (+3ms) or 20ms(+5ms) selectable, 120V dc: 3ms (+0.1ms) or 10ms (+1ms) selectable for Off to On transition
- Field-Replaceable Wiring: Uses a field wiring arm of 1771-WH, comparable to removable terminal blocks, for modular wiring and simplified installation and maintenance
- Status Indication: 1 green module active indicator and 16 red status indicators for system logic side indication at the front panel
Technical Specifications
- Input Channels: 16 points
- Input Voltage (AC): 79–138V AC, 50/60 Hz
- Input Voltage (DC): 79–138V DC
- Backplane Current Load: 195 mA
- Maximum Off-State Current: 3 mA (AC), 0.8 mA (DC)
- Power Dissipation: 8.8 W
- Thermal Dissipation: 30.1 BTU/hr
- Signal Delay (AC, 60 Hz): 5 ms (±3 ms)
- Signal Delay (DC): 3 ms (±0.1 ms) or 10 ms (±1 ms)
- Compatible Chassis: 1771-A1B, A2B, A3B, A3B1, A4B, 1771-AM1 and AM2 chassis
- Wiring Arm: 1771-WH
- Series: Series C (also available in Series B and D)
Typical Applications
The 1771-IAD is primarily used to interface discrete devices such as pushbuttons, switches of different varieties, auxiliary contacts from relays, contactors and other devices. Common uses include motor starter interlocks, limit switch inputs, pushbutton status monitoring, pilot light control feedback, and annunciator inputs. The module’s noise filtering and signal isolation make it suitable for harsh industrial environments with frequent electrical transients.
Compatibility & Replacements
The 1771-IAD/C is designed for direct installation into standard 1771 I/O chassis. When installing the 1771-IAD to any of the compatible chassis, it requires keying position between 10 and 12 or between 14 and 16. It is a series D module and supports ½, 1, and 2-slot I/O addressing. Note: As of March 10, 2020, the 1771 16 Point Digital Input Module will be discontinued and no longer available for sale. This unit represents surplus inventory suitable for maintenance, repair, and modernization (MR&M) applications, emergency replacement stock, and legacy system support.
