Allen-Bradley 1746-NO8V SLC 500 Analog Output Module

Product Overview

The Allen-Bradley 1746-NO8V is an analog output module designed for the SLC 500 programmable controller family. This module provides eight single-ended voltage output channels with a range of ±10.25V DC, making it suitable for precision control of modulating devices such as valves, dampers, variable frequency drives (VFDs), and louvers. Its 16-bit resolution and robust accuracy ensure reliable performance in demanding industrial environments.

Technical Specifications Breakdown

Key parameters for the 1746-NO8V are listed below for quick reference:

Industry Applications

This analog output module is a cost-effective solution for applications requiring precise voltage control. In process industries, it can regulate valve positioners and damper actuators, leveraging its ±10.25V DC range and 16-bit resolution for fine adjustments. For building automation, the 1746-NO8V interfaces with VFDs to control fan and pump speeds, improving energy efficiency. Its fast update time of 540 microseconds per eight channels supports real-time control loops in packaging or material handling systems.

Installation & Setup Guidance

Install the module into any 1746 chassis slot except slot 0, which is reserved for the processor. Ensure the backplane current consumption—120 mA at 5V DC and 160 mA at 24V DC (with J4 jumper set to RACK)—is within the chassis power budget. For external power operation, set the J4 jumper to EXT to draw 0 mA at 24V DC from the backplane. Wire output signals using single-ended connections, and configure the desired output voltage range and data format via the SLC 500 programming software. Available data formats include scaled engineering units, scaled for PID, proportional counts, 1746-NO4 format, and user-defined scale.

Maintenance & Reliability

The module operates reliably within a 0-60°C temperature range and 5-95% non-condensing relative humidity. It is CUL and CE-certified for Class I, Division 2 hazardous locations. Periodic inspection of the LED status indicators and field wiring connections helps ensure continued performance. The module's overall accuracy of 0.1% of full scale at 25°C and 0.2% at 60°C supports long-term stability in controlled environments.

Compatibility & Integration

The 1746-NO8V is fully compatible with all SLC 500 processors and any 1746 chassis slot except slot 0. It supports multiple SLC data formats and optional output data parameters such as output clamping limits, alarm limits, ramp rate/limit, preset fault values, and configurable output behavior under fault conditions (reset, hold, preset). These features allow seamless integration into existing control strategies.

Selection Guide & Purchasing Advice

When evaluating analog output modules for your SLC 500 system, consider the channel count, output type, and resolution. For current output needs, explore other SLC 500 analog modules. AutoDCSTech stocks this module and can assist with availability and lifecycle status. Please verify current lifecycle status and availability with AutoDCSTech before ordering.

Troubleshooting & Common Issues

If the module does not produce the expected output voltage, first check the J4 jumper setting (RACK vs. EXT) and ensure the backplane power supply meets the 5.6W consumption. Verify that the output coding range (-32,768 to +32,767) corresponds to the selected voltage range. If alarms are triggered, review the output alarm limits and ramp rate settings in the configuration. For persistent issues, inspect the field wiring for shorts or open circuits and confirm the load resistance is 1K ohm or greater.