Description

The Allen-Bradley 1756-OF4 is a non-isolated ControlLogix analog output module designed to provide reliable voltage and current control signals for industrial automation environments. Engineered to interface directly with the ControlLogix backplane, this module is capable of actuating modulating devices, final control elements, and proportional actuators, as well as retransmitting signals to external recorders, data loggers, indicators, and secondary controllers.

As part of the Allen-Bradley ControlLogix platform, the 1756-OF4 integrates seamlessly into standard 1756 chassis architectures. It supports high-resolution signal generation across both voltage and current ranges, ensuring precise command delivery in complex process and discrete control applications.

Features

• Four non-isolated analog output channels configurable for voltage or current signals
• Voltage output range of +/-10.4V DC with 15-bit resolution across 10.5V (320 microvolts per bit)
• Current output range of 4 to 20 mA (or 0 to 20 mA) with 15-bit resolution across 21 mA (650 nanoamps per bit)
• Direct backplane communication and power distribution via the 1756 ControlLogix chassis
• Open-style enclosure designed for standard industrial cabinet mounting
• On-board diagnostic reporting for open-circuit and out-of-range fault conditions

Applications

• Modulating valve and damper control in process industries
• Speed and torque reference generation for variable frequency drives
• Signal retransmission to strip chart recorders and data acquisition systems
• Setpoint distribution to external controllers and instrumentation loops

Technical Specifications

Connections / Interfaces

The 1756-OF4 module connects to field devices using a removable terminal block (RTB) such as the 1756-TBNH or 1756-TBSH (ordered separately). The terminal block provides secure screw or spring-clamp connections for field wiring. Shielded twisted-pair cabling is strongly recommended for all analog output channels to minimize the impact of electromagnetic interference (EMI) in industrial environments.

Installation Guidelines

• Ensure all power to the 1756 chassis is removed before installing or removing the module.
• Insert the module into any available slot in a 1756 ControlLogix chassis. The module is keyed to prevent incorrect insertion into incompatible chassis slots.
• Secure the module using the top and bottom latches, then attach the removable terminal block to the front housing.
• Terminate signal shields to a low-impedance earth ground at one end only, typically at the chassis ground bar, to prevent ground loops.