PLC 5 Discrete Input Module 120VAC 125VDC Allen Bradley 1771-IA

The 1771-IA is a Programmable Logic Controller (PLC) input component. This electronic hardware belongs to the legacy PLC5 product family of AB. This module features an embedded Eight (8) discrete input channels operating at 120VAC and 125VDC voltage category.

Discrete input modules provide interface to field instruments to monitor and evaluate their state. Field instruments such as Limit switches, auxiliary contacts, sensors and other devices.

This input module is provided with a wiring arm with part number 1771-WA. Wiring arms provide a modular means of terminating signal wire to the module which also contributes to the modularity if the system. In the event when the 1771-IA needs replacement, the wiring arm may be disconnected to preserve the existing wiring. This wiring arm may be directly connected to the replacement module.

This module is configured using RSLogix 5 programming software. This programming software supports ladder programming language. The 1771-IA input module is accessed within the programming software via the provided binary files. Binary files are data file types intended for discrete devices. To use this input module, it must be configured first using via the channel configuration. After configuration, the corresponding entry within the binary file is automatically created.

This module occupies a single slot of the 1771 PLC5 chassis. It can be installed to any available slot with consideration to the power supply capacity. It has backplane current draw of 75 mA, Power Dissipation of maximum 10.7 Watts and maximum Thermal Dissipation of 36.5 BTU/Hr. The individual channel’s On-state voltage range is 87VAC to 138VAC 97VDC to 138VDC.

The AB 1771-IA is a PLC 5 Digital AC/DC Input Module. It converts AC signals provided by user devices to the logic level needed by the processor. It controls the state of corresponding bits in the PLC data table. It interfaces input devices such as pushbuttons, limit switches, motor starters, and annunciators to interface with on/off sensors and actuators. It provides a modular design with space-saving features to add input to a PLC control system. It comes with a 1771-WA wiring for signal wiring termination and provides convenient wiring method. It is a series C module and supports 1/2, 1, and 2 slot I/O addressing.

The 1771-IA module has Eight (8) inputs with a 120V AC/DC voltage category. It has an operating voltage range of 87 - 138V AC or 97 - 138V DC. It has a typical signal delay of 24ms +/-10ms at on/off AC state and 10ms +/-4ms at on and 20ms +/-9ms at off DC state. It has a maximum Off-state current of 2.8mA and a backplane current load of 75mA. It has a maximum power dissipation of 10.7 W and a thermal dissipation of 36.5 BTU/hr. It is installed in a 1771 I/O chassis containing a PLC processor. Keying bands for putting it in the right slot are between pins 10 and 12 for upper connector and pins 4 and 6 for the lower connector.

The 1771-IA module has Eight (8) orange status indicators for field side indication at the front panel. It contains optoelectrical isolation to protect the system circuits from electrical transients. It also contains an input filtering feature to reduce electrical noise.