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Shared and Global Variable Issue with Motor VI


I have written a VI that will command a stepper motor to follow the desired profile and loop the profile until the user pushes the stop button. I modified the state machine example from LV to achieve this. I now want to connect a linear potentiometer to the linear actuator to verify that the distance I commanded the motor to travel is the actual distance that it traveled. I am using a NI 9219 module to collect the data from the potentiometer.

When I added the potentiometer to the program, the cRIO-9073 chassis that I am using immediately crashes and looses connection with the computer when I click the Run VI button. I looked into this a little more and it seems that the chassis will crash only when I add shared and global variables to the VI. I think it has something to do with the Network Variable Engine; I don’t have it installed on the chassis because the motor program alone will not run if it is installed on the chassis. Also, I have the chassis configured to the RT setting and not the FPGA setting.

I have attached a snippet of the code. I am using LV 2014 SP1 along with the SoftMotion module. The motor is connected to LV through a P70530 stepper drive which is connected to a NI 9512 module with the proper connectivity bundle. Is there something wrong with the VI that would cause the chassis to crash? Why will the simple motor VI not work when the Network Variable Engine is installed on the chassis? Thank you in advance for your help!

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Follow up to this post:

Sometimes when I try to connect the project to the chassis I get the following error: "Failed to load shared library taggerrt.out. Ensure that the library is present on the RT target. Use either MAX to install NI software or FTP to transfer custom librarier to the RT target."


I have tried re-installing the NI Device Drivers and reconfiguring the software on the cRIO chassis using MAX; however, the error keeps showing up. I read somewhere that the taggerrt.out library is a part of the Network Variable Engine but I don't know why it wouldn't be found when the NVE software is installed on the chassis. This message only comes up when I also have the SoftMotion Module software installed on the chassis. Has anybody else encountered this problem or know why this could be happening? Any ideas would be greatly appreciated! Thanks!

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Hi Triumph,


It could have to do with your cRIO running out of memory, though I am uncertain.


Can you try formatting your cRIO then reinstalling only the software you need?



Michael Bilyk

Applications Engineer


Michael Bilyk
Former NI Software Engineer (IT)
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