Allen-Bradley 1746-NO8V SLC 500 Analog Output Module

Allen-Bradley 1746-NO8V SLC 500 8-Channel Analog Voltage Output Module

Product Introduction

The Allen-Bradley 1746-NO8V significantly expands the analog control capabilities of SLC 500 systems. This Analog Output Module provides eight single-ended voltage output channels, and each channel delivers a versatile range of output signals. Specifically, it supports -10 to +10VDC, -10.25 to +10.25VDC, 0 to 10VDC, 0 to 5VDC, and 1 to 5VDC, offering exceptional flexibility for various field devices. Therefore, this module suits applications that need to drive modulating equipment such as valves, dampers, variable frequency drives (VFDs), and louvers. Its compatibility with any 1746 chassis slot except slot 0 makes system integration straightforward. Moreover, the 1746-NO8V incorporates advanced Class 3 configuration features, including ramping, clamping, alarming, and user-defined scaling, which significantly simplify ladder logic programming.

Technical Specifications

The 1746-NO8V excels in precision and performance within demanding industrial environments. It features eight (8) single-ended output channels, and the module employs an R-2R ladder network for digital-to-analog conversion. Each channel achieves a 16-bit resolution, equivalent to 320 µV per count, ensuring exceptional control granularity. The output coding follows a standard -32,768 to +32,767 integer format, which integrates seamlessly with SLC 500 data structures.

Additionally, this module offers outstanding accuracy across its operating temperature range. It achieves an overall accuracy of 0.1% of full scale at 25°C and 0.2% of full scale at 60°C. The maximum overall accuracy drift is only ±33 ppm per degree Celsius of full scale, guaranteeing stable performance even when ambient temperatures fluctuate. The module also provides a 2.5% over-range capability, extending to ±10.25V, which offers valuable headroom for control applications. The output load range is 1K ohm and greater, with a maximum load current of 10 mA.

Performance & Response Characteristics

The 1746-NO8V delivers impressive speed and responsiveness for dynamic control loops. Its output step response reaches 95% of full scale within just 1 millisecond, making it suitable for applications requiring rapid actuator response. For channel updates, the module processes all eight channels in approximately 5 milliseconds for Class 1 operation and 10 milliseconds for Class 2 operation. This efficient update rate ensures timely delivery of control signals to all connected devices. Furthermore, the module features a field-wiring-to-backplane isolation rating of 500 Volts DC, which effectively protects the processor and chassis from potential electrical faults.

Configuration & Operating Modes

The 1746-NO8V offers extensive configuration flexibility to accommodate diverse application requirements. It supports multiple SLC data formats, including scaled engineering units, scaled-for-PID values, proportional counts, the legacy 1746-NO4 format, and user-defined scales. For each channel, you can independently select the nominal output voltage range from five available options. Moreover, the module provides a comprehensive set of optional output data parameters. These include user-defined scale limits, output clamping limits, output alarm limits, ramp rate or ramp limit settings, preset fault values, and configurable output behavior under fault conditions (reset, hold, or preset). You can also enable alarm latching and reset latched alarms as needed. To configure the module, you must enter specific ID codes into RSLogix 500. For Class 1 operation, use ID code 7052. For Class 3 operation, the ID code is 7053.

Mechanical & Environmental Parameters

This SLC 500 module withstands the conditions of typical industrial environments. It comes in an open-type enclosure, and you can mount it in any 1746 chassis slot except slot 0. The module's ambient operating temperature ranges from 0 to 60 degrees Celsius, ensuring reliable performance in warm control cabinets. It also tolerates a non-condensing relative humidity of 5 to 95% for both operation and storage. For status monitoring, the 1746-NO8V includes LED indicators that display both module health and individual channel status. Additionally, the module carries cUL and CE certifications, making it suitable for use in Class I, Division 2 hazardous locations. Its robust construction handles operational shock up to 30G and vibration of 5G at 10-500Hz.

Packaging List

• 1 x 1746-NO8V Analog Voltage Output Module

• 1 x Removable Terminal Block (RTB)

• 1 x Installation Instructions Guide

Frequently Asked Questions (FAQ)

1. What voltage output ranges does the 1746-NO8V support?
The 1746-NO8V offers five selectable output ranges per channel. These include -10 to +10VDC, -10.25 to +10.25VDC, 0 to 10VDC, 0 to 5VDC, and 1 to 5VDC, providing great flexibility for different field devices.

2. How do I choose between Class 1 and Class 3 operation?
Class 1 provides basic output functionality compatible with simpler applications. Class 3 unlocks advanced features like user-defined scaling, ramping, clamping, alarming, and fault behavior configuration. Your choice depends on the complexity of your control requirements.

3. What are the ID codes for configuring the 1746-NO8V?
For Class 1 operation, enter ID code 7052. For Class 3 operation, enter ID code 7053. You must enter the correct code in the I/O Configuration section of RSLogix 500.

4. How accurate is the 1746-NO8V over temperature changes?
The 1746-NO8V maintains excellent accuracy, with 0.1% of full scale at 25°C and 0.2% at 60°C. Its maximum overall accuracy drift is only ±33 ppm per degree Celsius, ensuring reliable performance across varying temperatures.

5. Can I remove the 1746-NO8V while the system is powered on?
No, you must never remove or install this module under power. Doing so can cause electrical arcing, potentially harming the module and other components. Always power down the chassis before installation or removal.