Purchase now: Allen Bradley 1746-NI8 Analog Input Module
Purchase now: Atlantechdrives provides you the 1746-NI8, an advanced, high-density analog input module designed for the Allen Bradley SLC 500 programmable logic controller system. This module effectively doubles the capacity of the standard 4-channel version, providing 8 highly accurate analog input channels in a single chassis slot. It is an indispensable component for complex automation systems requiring the continuous monitoring of multiple variables, such as flow rates, temperatures, pressures, and load cell weights. The true strength of the 1746-NI8 lies in its universal flexibility; each of the 8 channels can be individually configured to accept either voltage or current signals, allowing panel builders to consolidate different sensor types onto one single circuit board, saving valuable rack space and reducing overall hardware costs.
Technical Specifications of the 1746-NI8
The 1746-NI8 utilizes state-of-the-art analog-to-digital (A/D) converters to deliver 16-bit resolution, ensuring that even the most minute changes in the field process are accurately reported to the PLC processor. The module provides high common-mode noise rejection and excellent isolation.
- Part Number: 1746-NI8
- Module Type: High-Density Analog Input
- Compatible System: SLC 500 (1746 Series)
- Number of Channels: 8 Differential or Single-ended inputs
- Selectable Ranges (Voltage): +/- 10V DC, 0 to 10V DC, 1 to 5V DC, 0 to 5V DC
- Selectable Ranges (Current): 0 to 20 mA, 4 to 20 mA, +/- 20 mA
- Resolution: 16-bit
- Backplane Current Draw: 200 mA at 5V DC, 100 mA at 24V DC
- Configuration: Physical DIP switches per channel
Installation Advice: DIP Switch Setup
The most critical step during the installation of the 1746-NI8 happens before you even insert it into the chassis. Expert Tip: This module relies on physical DIP switches located on the circuit board to determine whether a specific channel operates in Voltage (V) or Current (mA) mode. You must configure these switches precisely according to your wiring schematic. If a channel is accidentally left in «Current» mode (which engages an internal shunt resistor) and a 10V DC or 24V DC signal is applied, the excessive current will permanently burn out that channel. Always double-check the switch banks, and remember that software configuration in RSLogix 500 must perfectly match the physical DIP switch settings for the module to scale the data correctly.
Maintenance and Noise Reduction
When routing cables to the 8 channels, electrical noise is your biggest enemy. Always use high-quality, shielded twisted-pair cables. Strip the shield back and connect the drain wire to the chassis ground terminal near the PLC—never ground the shield at both the PLC and the sensor end, as this creates a ground loop that will cause your analog readings to fluctuate wildly. If readings remain unstable, use the advanced configuration in your programming software to increase the digital filter settings for that specific channel.
Frequently Asked Questions (FAQs)
Q: Can I mix 4-20mA and 0-10V sensors on the same 1746-NI8 module?
A: Yes, absolutely. Each of the 8 channels is fully independent and can be set to either voltage or current via the onboard DIP switches, offering maximum flexibility.
Q: Does the module supply loop power to my 4-20mA sensors?
A: No. The 1746-NI8 is a passive receiver. You will need an external 24V DC power supply to provide power to the field sensors.
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For expanded process monitoring, this 8-channel unit can be upgraded to the 1746-NI16I 16-channel card.
