Purchase now: Allen Bradley 1746-NI4 Analog Input Module
Purchase now: Atlantechdrives provides you the 1746-NI4, the universally trusted and highly versatile 4-channel analog input module for the Allen Bradley SLC 500 automation platform. Unlike the high-density NI16 modules which are strictly limited to either voltage or current, the 1746-NI4 is a hybrid powerhouse. It offers 4 distinct, differential input channels, each of which can be individually configured to read either voltage (0-10V, +/-10V) or current (4-20mA). This immense flexibility makes it the go-to module for standard machinery, allowing technicians to mix and match different types of analog sensors—such as a voltage-based laser distance sensor and a current-based pressure transducer—on a single, highly reliable circuit board.
Technical Specifications of the 1746-NI4
The 1746-NI4 utilizes a robust 16-bit analog-to-digital converter, ensuring that process variables are captured with extreme fidelity. The use of «differential» inputs means that each of the 4 channels has its own dedicated positive and negative terminals, which provides vastly superior common-mode noise rejection compared to single-ended modules.
- Part Number: 1746-NI4
- Module Type: Configurable Analog Input
- Compatible System: SLC 500 (1746 Chassis)
- Number of Channels: 4 Differential inputs
- Selectable Ranges: +/- 10V DC, 0-10V, 1-5V, 0-20mA, 4-20mA
- Resolution: 16-bit
- Configuration Method: Physical DIP Switches
- Backplane Current Draw: 25 mA at 5V DC, 85 mA at 24V DC
- Isolation: High optical isolation per channel
Expert Tips: The Critical Importance of DIP Switches
Hardware configuration is the number one cause of failure on this specific module. Expert Tip: The 1746-NI4 uses physical DIP switches located on the side of the printed circuit board to select whether a channel operates in Voltage mode or Current mode. You must set these switches before sliding the module into the chassis. If a channel is wired to receive a 24V DC or 10V DC signal, but the DIP switch is accidentally left in the «Current (mA)» position, the module will engage an internal 250-ohm shunt resistor. The high voltage will push massive current through this tiny resistor, permanently burning out the channel in seconds. Always double-check your DIP switch settings against your wiring diagram before applying power to the panel.
Maintenance and RSLogix 500 Configuration
Maintenance on the 1746-NI4 is straightforward thanks to its removable terminal block (RTB), allowing for swift module replacement without wire disruption. Within your RSLogix 500 software, ensure you configure the advanced setup for the module. You can select different filter frequencies to smooth out noisy signals. If you are experiencing fluctuating readings from a 4-20mA sensor, lowering the filter cut-off frequency in the software configuration will drastically stabilize the value seen by the PLC processor.
Frequently Asked Questions (FAQs)
Q: Can I run two channels as 4-20mA and two channels as 0-10V DC?
A: Absolutely. Each of the 4 channels is completely independent. You configure the hardware DIP switches for each specific channel, allowing for any combination of voltage and current inputs on the same card.
Q: What does «Differential Input» mean and why is it better?
A: Differential inputs use two wires (IN+ and IN-) for every signal, rather than sharing a common ground. The module measures the difference between these two wires, which naturally cancels out any electromagnetic noise (EMI) picked up along the cable run, providing a much cleaner signal in heavy industrial environments.
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This 4-channel analog card is a standard fit for SLC 500 setups using the 1746-A4 4-slot chassis.
