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Why is the Interlock LED on my UMI-7774/7772 Always On?

Hardware: Motion Control

The Interlock LED on my UMI-7774/7772 is always on, and the Disabled LED is always on for all my axes. How do I turn these LEDs off?

The host bus interlock is a safety feature that monitors the +5V pin from the motion controller to verify that the motion controller is powered on and properly connected to the UMI-7774. When the motion controller and the UMI-7774 are not properly connected, the Interlock LED on the UMI-7774 will light up and all axes will be disabled.

To turn off the Interlock LED, try the suggestions below:
  • Make sure that you have a motion cable connecting the correct Motion I/O connector of your motion controller to the Motion I/O connector on your UMI-7774. The Interlock LED will be lit if you are connected to the Digital I/O connectors instead.
  • Make sure all cable connections are secure.
  • Make sure the computer is on. If the computer is off, the motion controller will not be powered on.
  • Probe the +5V line on the motion controller using a separate breakout connection, such as the SCB-68.  This will test if the host card is supplying the correct voltage, and can indicate a damaged card.
  • Check that the motion card is recognized in MAX. If the card is not recognized in MAX, it may be damaged.
If all of the above has been checked and the Interlock LED is still lit, then your UMI may be damaged. Please contact NI Technical Support for further assistance.

Related Links:
KnowledgeBase 14H8FRIT: Difference between a Universal Motion Interface and a Passive Terminal Block
KnowledgeBase 3VG9BKD3: Why Do I Have to Supply Power to the UMI-7764?


Report Date: 06/05/2006
Last Updated: 08/25/2014
Document ID: 3Y4DLNS4

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