Allen-Bradley 1746-NO4I SLC 500 Analog Output Module

Description

The 1746-NO4I is a 4-channel current analog output module designed for use within SLC 500 automation control systems. It provides 4 non-isolated current output channels that convert 16-bit binary values from the SLC processor into continuous analog current signals. The module operates using backplane power from the 1746 chassis or through an external user-supplied 24V DC power supply to reduce backplane power supply loading. Connection to field devices is established via a 18-point removable terminal block.

Features

• Features 4 non-isolated current output channels.
• Configurable power source selection using an onboard DIP switch (SW1) for backplane or external 24V DC power.
• Communicates with the processor using 16-bit Two's Complement Binary data format.
• Supports field wiring to backplane isolation rated at 500V DC.
• Includes a removable terminal block for convenient maintenance and module replacement.
• Front panel features a Power Status LED that indicates when backplane power is active.

Applications

• Analog current loop control driving field control elements.
• Variable frequency drive speed reference signal generation.
• Control valve positioning and proportional actuator interfacing.
• Industrial process control loops utilizing 4 to 20 mA or 0 to 20 mA current signals.

Technical Specifications

Connections/Interfaces

Installation Guidelines

• Power Interruption: Disconnect power from the SLC 500 system and external sources before installing, removing, or wiring the module.
• Power Selection: Set the onboard DIP switch (SW1) to UP when using an external 24V DC power source, or DOWN to power the module from the chassis backplane.
• Chassis Mounting: Align the module circuit board with the chassis card guides and slide the module into the slot until top and bottom retaining clips snap in place.
• Slot Placement: Position the module in a chassis slot away from AC or high-voltage DC modules and away from the system power supply to reduce noise exposure.
• Wiring Practice: Use Belden 8761 shielded twisted-pair cable for signal wiring. Ground the drain wire and foil shield at the load end, or at the chassis mounting tab if grounding at the load is not feasible.
• Terminal Block Installation: Secure connections on the removable terminal block using a maximum torque of 0.57 Nm (5 lb-in). Do not jumper unused output terminals.

Compliance and Certifications

• CULUS C-UL Listed Industrial Control Equipment
• CE Marked for all applicable directives
• C-Tick Marked for all applicable acts
• Functional Safety TUV certified according to DIN V 19250 and IEC 61508 (1002D, AK 1 to 6, SIL 1 to 3)
• Category 1 to 4 according to EN954-1