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How to use LabView to measure distance using quadrature encoder

I am currently doing a project that requires the positioning and characterization of TV signals. As such, the position of the TV receiver is one  important variable that i have to measure. I am required to automate the measurements and data logging using a PC/notebook. I have purchased a 2-channel HEDS-9000 quadrature encoder with 2000 CPR & the HEDS6120 codewheel - both from Avago Tech, to be interfaced with the notebook/PC. My idea is to get a TTL-to-RS232 converter to interface with the PC, so that i can feed the output from the encoder to the PC. However, i dun have much idea on how I can use LabView to interface the encoder and the PC. Can anyone offer some valuable advice? Do I need additional hardware for it?

Btw, the encoder module consists of 5 pins - Vcc, GND, CH.A, CH.B, with one pin not used.

Thanks !!
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Hello Involver,

National Instruments does not offer any devices to directly interface a quadrature encoder with the serial port on a PC. However, most of our data acquisition (DAQ) boards do have counters, which can be used to take measurements from a quadrature encoder. For some information about how to interface a DAQ board with an encoder, you can reference this document or for more details you can go here.

This is a list of National Instruments' devices which should be compatible with the quadrature encoder you described. The devices listed on that page have two counters each, which allows them to count bi-directionally (up and down). There are some example programs on the NI Developer Zone which show how to program quadrature encoders in LabVIEW with various National Instruments' DAQ cards here, here and here.

I hope this information is helpful. Let me know if there is anything else I can do to help.

Matt Anderson

Hardware Services Marketing Manager
National Instruments
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I need to read encoder position with labview. I have a quadrature encoder an PCI-6023e daq card.

I can read encoder count but i'd to count up clockwise and count down anti-clockwise. But with E-series card i can have the daqmx create channel option : angular position.

So how i can have rotational information on my encoder?

Does anyone have a solution ?




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Hi Jerome,

E-series don't support encoder directly.

Consider using M-series,,n23:5971,n24:PCI,n36:14/lang/en/nid/1036/ap/daq/ps/25, if you wish to acquire a position using an encoder.

Regards, Kate
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Message 4 of 5

Hello Jerome and Kate,


While certain task types and features are limited to M Series devices, there is still a lot of functionality that exists with E Series devices. I would recommend that you examine these two resources to see if your current device can accomplish what you need:

NI Tutorial: Using Quadrature Encoders with E Series DAQ Boards

NI Example Program: Quadrature Encoder with E Series Devices Using


Matt Anderson

Hardware Services Marketing Manager
National Instruments
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