Purchase now: Allen Bradley 1746-NO4V Analog Voltage Module
Purchase now: Atlantechdrives provides you the 1746-NO4V, a precision analog output module designed by Allen Bradley for the proven SLC 500 programmable controller family. Unlike its current-generating sibling, the 1746-NO4V is engineered exclusively to produce Voltage (V DC) signals. It provides 4 independent output channels capable of generating 0 to 10V DC or bipolar +/- 10V DC signals. This module is the industry standard for controlling field devices that require a voltage reference, such as legacy servo amplifiers, proportional hydraulic positioners, and specific motor speed controllers, allowing for highly dynamic and precise motion or flow control.
Technical Specifications of the 1746-NO4V
The 1746-NO4V uses a 14-bit DAC to deliver excellent signal resolution. Its ability to output a bipolar +/- 10V signal makes it indispensable for servo applications where positive voltage commands forward motion, negative voltage commands reverse motion, and exactly zero volts commands a hard stop.
- Part Number: 1746-NO4V
- Module Type: Analog Output Module
- Signal Type: Voltage (V DC) Only
- Number of Channels: 4 Single-ended outputs
- Output Ranges: -10 to +10V DC, 0 to +10V DC
- Resolution: 14-bit
- Minimum Load Impedance: 1,000 Ohms (1 kOhm)
- Backplane Current Draw: 55 mA at 5V DC, 145 mA at 24V DC
- External Power Required: 24V DC
Expert Tips: Mitigating Voltage Drop and EMI
Voltage analog signals face two major enemies on the factory floor: voltage drop and electromagnetic interference (EMI). Expert Tip: Because the 1746-NO4V relies on voltage amplitude to convey data, long cable runs are detrimental. Wire resistance will consume some of the voltage, meaning a 10.0V output at the PLC might arrive as 9.5V at the drive. Keep cable runs to voltage-controlled devices as short as possible (ideally under 50 feet). Furthermore, voltage cables act like antennas for noise. You must use high-quality, shielded twisted-pair cables. Critically, ground the cable shield only at one end (usually at the PLC chassis earth ground). Grounding both ends creates a «ground loop,» which will induce severe noise and cause your controlled servo or valve to jitter erratically.
Maintenance and Short-Circuit Considerations
The 1746-NO4V features internal circuitry designed to protect against brief short circuits on the field wiring. However, a prolonged dead-short across the voltage output terminals can overheat and permanently damage the digital-to-analog converter chips. During routine maintenance or initial commissioning, always use a digital multimeter to verify that the field wiring has an impedance of at least 1,000 ohms before connecting the terminal block to the powered module.
Frequently Asked Questions (FAQs)
Q: Can I use this module to drive a 4-20mA device?
A: No. The 1746-NO4V outputs voltage only. If you connect it to a device expecting a 4-20mA signal, the device will not operate correctly, and the low impedance of the current input could overload the voltage module.
Q: How do I configure the output range (+/-10V vs 0-10V)?
A: The output ranges are configured entirely via software (such as RSLogix 500) within the advanced I/O configuration tab for the specific chassis slot.
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To manage proportional voltage signals in your system, ensure this module is housed in a robust 1746-A4 compact chassis.
