1746-NO4V Allen-Bradley SLC 500 Analog Voltage Output Module

Product Overview

• The 1746-NO4V is a high-precision analog output solution specifically designed for SLC 500 modular and fixed hardware platforms.
• This Analog Output Module provides four (4) non-isolated voltage channels, delivering a full-scale signal range of -10 to +10 VDC.
• Utilizing an R-2R Ladder conversion method, the 1746-NO4V achieves 14-bit resolution for smooth actuator control.
• It is a factory-calibrated component that ensures seamless integration with SLC processors for closed-loop control applications.

Technical Specifications

• Brand: Allen-Bradley / Rockwell Automation
• Model: 1746-NO4V
• Series: SLC 500
• Output Channels: Four (4) Point, Non-Isolated
• Voltage Range: -10 to +10 VDC (-1 LSB)
• Resolution: 14 Bits
• Conversion Method: R-2R Ladder
• Parallel Update Time: 512 microseconds (all channels in parallel)
• Step Response: 2.5 milliseconds (at 95%)
• Backplane Current: 55 mA @ 5V / 145 mA @ 24V
• External Power: 24VDC (Configurable via SW1 switch)
• Isolation: 500V DC field wiring to backplane
• Maximum Load: 10 mA current / 1 µF reactance
• Accuracy Drift: +/- 54 ppm/degree Celsius full scale

Global PLC Spare HUB's Insight

• The 1746-NO4V remains an engineering staple for legacy SLC 500 systems requiring fast voltage modulation.
• From a technical perspective, its parallel update time of 512µs is exceptional for high-speed synchronization tasks.
• The dual-power option (Backplane vs. External 24V) is a critical design feature; using an external supply via SW1 reduces the thermal load on the rack.
• This module is sensitive to electrical noise; we strongly advise installing it at the furthest possible point from AC power modules.

Application Scenarios & Equipment Pairing

• Variable Frequency Drives (VFDs): Providing -10 to +10V speed reference signals for bidirectional motor control.
• PID Control Loops: Acting as the final control element interface for proportional valve positioning.
• Signal Re-transmission: Sending local PLC values to SCADA systems or paper chart recorders for regulatory logging.
• Load Sharing Coordination: Synchronizing multiple stand-alone controllers by providing a unified reference voltage.
• HMI/SCADA Manual Overrides: Translating operator-entered values into physical voltage levels for manual process trimming.

Diagnostic & Installation Capabilities

• Status Monitoring: Equipped with a front-panel LED indicator for immediate module health and power verification.
• Removable Terminal Block (RTB): Allows for rapid module replacement without disconnecting individual field wires.
• Factory Calibration: Eliminates the need for periodic manual potentiometer adjustments in the field.
• Noise Mitigation: Recommended installation in the chassis nearest to the enclosure bottom for better ambient temperature management.

Commercial & Logistics Terms

• Warranty: Comprehensive 12-month industrial-grade hardware replacement warranty.
• Fast Dispatch: Guaranteed shipment within 24 to 48 hours of order confirmation.
• Global Shipping: Reliable express delivery via FedEx, UPS, and DHL.
• Condition: Professionally inspected and packed in an open-style industrial chassis mount format.

Selection & Buying Guide

• Power Budgeting: If your rack power supply is near capacity, utilize an external 24VDC supply via the SW1 toggle.
• Grounding Awareness: Since this is a non-isolated module, ensure field devices share a compatible ground reference to avoid loops.
• Wiring Discipline: Use #14 AWG maximum wire size and limit termination to two wires per point for proper cover closure.
• Thermal Planning: Avoid placing the 1746-NO4V directly adjacent to high-heat power supplies or AC modules.

Frequently Asked Questions (FAQ)

• How do I switch from backplane power to an external 24VDC power supply?
• Locate the SW1 switch on the module circuit board and set it to "External" before installation in the chassis.

• Does the 1746-NO4V support "Hot-Swapping" or removal under power?
• No. Removing the module while the chassis is energized can cause electrical arcs, causing permanent damage to the circuitry.

• What is the significance of the 14-bit resolution for my process?
• It divides the voltage range into 16,384 increments, providing fine control over valves and reducing PID "hunting."

• Why should I install the module away from AC voltage sources?
• Analog signals are susceptible to electromagnetic interference; physical separation ensures output signal purity and accuracy.

• What programming format does the module use for voltage output?
• It uses a 16-bit two's complement binary format, representing a digital range of -32,768 to +32,764.

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