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

Product Overview

The Allen-Bradley 1746-NO4V is a non-isolated analog output module from the SLC 500 series, manufactured by Rockwell Automation. It features four output channels that generate voltage signals ranging from -10 to +10 VDC. This module is designed for use with SLC 500 fixed or modular style hardware, making it a versatile choice for existing installations. Its primary function is to convert digital control commands into analog voltage outputs for driving external devices like variable frequency drives, chart recorders, or valve positioners.

Technical Specifications Breakdown

Key parameters for the 1746-NO4V are listed below for quick reference:

Industry Applications

Process Control in Chemical Plants

In chemical processing, the 1746-NO4V module can output voltage signals to control proportional valves based on PID loop calculations. Its 14-bit resolution ensures fine granularity, while the 512 µs update time supports fast loop response. This prevents overshoot and maintains product quality.

Load Sharing in Power Generation

For generators that require load sharing, this module transmits reference signals between controllers. The -10 to +10 VDC range allows bidirectional control, and the 2.5 ms step response ensures stable coordination during load changes.

Retransmission for Monitoring Systems

In SCADA environments, the module retransmits process variables to remote recorders or indicators. The high accuracy and low drift reduce calibration needs, lowering operational costs over time.

Installation & Setup Guidance

When installing the 1746-NO4V, mount it in a 1746 chassis away from AC sources or high-voltage DC lines to minimize electrical noise. Choose a slot near the enclosure bottom for better ambient temperature conditions. Use #14 AWG wire maximum, and limit two wires per terminal to allow cover closure. This module does not support removal under power—always de-energize before handling. For power, if backplane current is insufficient, activate SW1 to use an external 24 VDC supply. The module uses a 16-bit two’s complement binary format for communication.

Maintenance & Reliability

Inspect the module periodically for dust accumulation and ensure ambient temperature stays within 0 to 60 degrees Celsius. The non-condensing relative humidity range is 5 to 95%. The LED status indicator provides quick visual feedback on operational status. Avoid exposing the module to temperatures outside the non-operating range of -40 to 185 degrees Fahrenheit. Regular checks of the removable terminal block (RTB) connections prevent signal degradation.

The Challenge of Precise Voltage Control in SLC 500 Systems

In many industrial automation setups, achieving accurate voltage output for process control is critical. Consider a scenario where a chemical plant needs to regulate valve positions based on a PID controller. The Allen-Bradley 1746-NO4V module provides a reliable solution, delivering precise -10 to +10 VDC signals from the SLC 500 platform. This component ensures that analog commands from HMIs or SCADA systems translate into real-world actuator movements without drift or noise interference.

Compatibility & Integration

It communicates via the backplane using 16-bit two’s complement coding. The module can be assigned to PID controller outputs, mathematical results, or manual HMI values. It also supports retransmission for other devices. Field wiring to backplane isolation is rated at 500 Volts DC, ensuring signal integrity.

Selection Guide & Purchasing Advice

When selecting the 1746-NO4V, verify that your SLC 500 chassis has available slots and sufficient backplane current (55 mA at 5V, 145 mA at 24V). For new installations, consider the total number of analog outputs needed. AutoDCSTech offers this module with expert support to ensure correct integration. Please verify current lifecycle status and availability with AutoDCSTech before ordering.

Troubleshooting & Common Issues

If output signals are erratic, check for noise sources near the module and ensure proper grounding. Verify that the backplane power supply meets current requirements. If the module does not respond, inspect the LED indicator and confirm the removable terminal block is seated correctly. For calibration concerns, note that the module is factory calibrated; field adjustments are not recommended without proper equipment.