1746-NI8 | Allen-Bradley SLC 500 Analog Input Module, 8 Channels

The 1746-NI8 is an 8-channel analog input module for the Allen-Bradley SLC 500 system. It accepts both voltage and current signals, configurable per channel, and converts them into digital values for use by the processor. It is ideal for applications requiring precise and rapid analog data acquisition, such as process monitoring and closed-loop control.

Yes, this module can handle voltage inputs such as 0–10V DC, 1–5V DC, 0–5V DC, and ±10V DC, as well as current inputs like 0–20 mA, 4–20 mA, and ±20 mA. Signal type selection is done individually for each channel using onboard DIP switches, providing flexibility in mixed-signal environments.

The module features eight differential analog input channels. Each can be configured for either voltage or current input, and all are processed using a built-in low-pass filter and programmable filter frequency settings (from 1 Hz to 75 Hz) to minimize noise and enhance signal clarity.

Yes, it is compatible with SLC 5/01 through 5/05 processors. However, SLC 5/01 supports only Class 1 operation, while SLC 5/02 through 5/05 support both Class 1 and Class 3, which allows for advanced data handling and user-defined scaling of input signals.

To correctly wire a 3-wire potentiometer (Positive, Negative, Signal) to a channel of the 1746-NI8 analog input module:

• Connect the positive (V+) wire of the potentiometer to a +10 VDC power supply.
• Connect the negative (V−) wire to the IN− terminal of the selected analog input channel.
• Connect the signal (wiper) wire to the IN+ terminal of the same channel.
  
  

The SHIELD terminal is used for cable shielding and should be connected to the drain (ground) wire of your analog signal cable, if available. If your potentiometer cable does not include a shield or drain wire (as mentioned in your case), then you can leave the SHIELD terminal unconnected, or optionally ground it at the controller end only to reduce electrical noise.

Also, note that if the channel status LED is off, this likely means the input channel is not enabled in the ladder logic configuration or the input type hasn't been properly set in the controller. Be sure to enable the analog input channel and configure it for the correct voltage range (e.g., 0–10 VDC) in your SLC 500 software (such as RSLogix 500) and ensure scaling is applied to interpret the potentiometer’s position correctly.

No, the 1746-NI8 will be discontinued on September 30, 2024, as announced by Rockwell Automation. It will no longer be available for purchase after this date. Customers are advised to plan for migration, as the replacement falls under the "Engineering Replacement" category, requiring evaluation of compatibility and rewiring.