Purchase now: Allen Bradley 1746-NO8V Analog Voltage Module
Purchase now: Atlantechdrives provides you the 1746-NO8V, a high-density, high-precision analog output module designed by Allen Bradley for the highly reliable SLC 500 programmable controller family. While standard analog modules offer 4 channels, the 1746-NO8V doubles your capacity, providing 8 independent output channels exclusively dedicated to generating Voltage (V DC) signals. This module is the ultimate solution for complex motion control and process applications requiring the simultaneous command of multiple variable frequency drives (VFDs), proportional hydraulic valves, legacy servo amplifiers, and chart recorders. By delivering 8 high-resolution voltage outputs from a single chassis slot, it drastically reduces panel size and lowers the cost per channel in large-scale automation projects.
Technical Specifications of the 1746-NO8V
The 1746-NO8V translates 16-bit digital values from the PLC processor into smooth, continuous analog voltage signals. Its standout feature is its ability to generate Bipolar (+/- 10V DC) signals, which is mathematically essential for bidirectional servo motor control (positive voltage for forward, negative voltage for reverse).
- Part Number: 1746-NO8V
- Module Type: High-Density Analog Output
- Signal Type: Voltage (V DC) Only
- Number of Channels: 8 Single-ended outputs
- Output Ranges: -10 to +10V DC, 0 to +10V DC
- Resolution: 16-bit (Excellent precision)
- Minimum Load Impedance: 1,000 Ohms (1 kOhm)
- Backplane Current Draw: 120 mA at 5V DC, 160 mA at 24V DC
- External Power Required: 24V DC
Expert Tips: Shielding and Voltage Drop Mitigation
Packing 8 voltage outputs into one module requires strict adherence to electrical best practices. Expert Tip: 0-10V DC signals are highly susceptible to «voltage drop» and electromagnetic interference (EMI). If you run an output wire 200 feet to a VFD, the copper’s resistance might reduce a commanded 10.0V signal down to 9.2V, meaning the motor will never reach maximum speed. Keep cable runs as short as possible. Furthermore, voltage signals act like antennas for factory noise. You must use high-quality, individually shielded twisted-pair cables for all 8 channels. Crucially, connect the shield drain wire to earth ground at the PLC chassis end only. Grounding both ends creates a ground loop that will inject noise directly into your analog signals, causing your controlled valves or motors to jitter erratically.
Maintenance and External Power Supply
A frequent troubleshooting blind spot with the 1746-NO8V is the external power requirement. The SLC backplane provides power for the module’s logic, but the actual voltage signals sent to the field are generated using an external 24V DC power supply wired to the module’s front terminal block. If all 8 outputs suddenly drop to zero volts while the PLC remains in RUN mode, check the external 24V supply and its associated fuses. An overloaded external supply will completely disable the output capabilities of this module.
Frequently Asked Questions (FAQs)
Q: Can I configure some channels for 4-20mA current?
A: No. The «V» in the 1746-NO8V part number indicates that it is hardware-locked to generate Voltage only. If your application requires high-density current outputs, you must purchase the 1746-NO8I module.
Q: Are the 8 output channels isolated from each other?
A: The 1746-NO8V provides optical isolation between the field wiring and the PLC backplane. However, the 8 output channels are «single-ended,» meaning they all share a common return (V DC Common) internally and are not isolated from one another.
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For proportional voltage control across 8 channels, this module is ideally housed in a 1746-A10 industrial chassis.
