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How Can I Trigger an Event Off of an Encoder Line (A, B, or Z)?

Primary Software: Driver Software>>NI-Motion/FlexMotion
Primary Software Version: 8.0
Primary Software Fixed Version: N/A
Secondary Software: LabVIEW Development Systems>>Professional Development System
Hardware: Motion Control>>Controllers>>PCI-7344

Problem:
I would like to trigger an event on my 733x, 734x, or 735x motion controller card based off of an encoder line (A, B, or Z).  How can I do this?

Solution:
Using a Universal Motion Interface, such as the UMI-7764, you can physically connect an encoder line to a trigger line.  For example, you can connect INDEX1 with TRIG1 to trigger an event based on the index signal of the axis 1 encoder.

If using a UMI is not an option, consider creating a custom jumper connection between two RTSI pins on your motion controller card.  You can then use two instances of Select Signal.flx to first route an encoder line to a RTSI line and then route another RTSI line (connected to the first via your custom jumper) to a High-speed Capture line. 

Select Signal.flx is a VI that allows you to route various motion signals by selecting source and destination values in software.  When the destination is RTSI[0..7] or PXI Star Trigger, the motion controller drives the RTSI line as an output. When the destination is High-speed Capture[1..8], the RTSI line serves as an input for the high-speed capture circuitry.

For a Destination value of High-speed Capture[1...8], the valid Source values are as follows:
  1. RTSI[0...7]
  2. PXI Star Trigger
  3. Trigger input
For a Destination value of RTSI[0...7], the valid Source values are as follows:
  1. Breakpoint[1...8]
  2. RTSI Software Port
  3. Phase A[1...8]
  4. Phase B[1...8]
  5. Index[1...8]
Note: You must route signals from the RTSI line before you enable high-speed capture.

Related Links:
Developer Zone Tutorial: Quadrature Encoder Fundamentals

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Report Date: 10/09/2007
Last Updated: 10/30/2007
Document ID: 4E8A7BQ7

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