Wiring an Encoder to the NI 9411 Module

Updated Apr 24, 2023

Reported In

Hardware

  • NI-9411

Driver

  • NI-DAQmx

Issue Details

I'm trying to wire my differential or single-ended encoder to my NI-9411, but I'm not sure of the pinout and the LabVIEW Examples only include three terminals (A.B and Z index) while documentation mentions there can be six (A+, A-, B+, B-, Z+ and Z-). How do I wire the encoder to the module?

Solution

The A, B and Z channels correspond to the encoder outputs and there maybe three or six depending on whether the encoder is differential (two wires per channel) or single-ended (one wire per channel). Both can be used with the NI 9411.

You can check the device pinout in NI MAX or find it in the NI 9411 Getting Started Guide to notice it has two inputs per channel, one positive and one negative, also explained in Using the NI 9411 Inputs as Differential or Single-Ended.

Connecting a Differential Encoder (two wires per channel)
Wire the positive and negative A, B and Z outputs from the encoder as shown in the figure below.
 

 
Connecting a Single-Ended Encoder (one wire per channel)
Connect the A, B and Z terminals from the encoder to the positive channel inputs in the module. Leave any negative inputs unwired.
 

Additional Information

To power the encoder using the 5 V pins on the NI 9411 module, you have to plug in an external power supply to the Vsupp and COM terminals on the NI 9411.

Depending on your encoder, it might be needed to to add a pull-up or pull-down resistors to get appropriate measurements. Those resistors are needed to make sure the appropriate voltage levels are provided to the Digital Input. Refer to the NI 9411 Datasheet to learn more about the required logic levels and other relevant specifications.

Not all encoders have a Z output. If your encoder does not, just leave the corresponding channels unwired.

Related Links

Why Does NI 9411 Read 1.5V Between COM and the Digital Inputs?

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