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Visa is only able to show my parallel port when run with sudo

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I am trying to talk to a monochrometer through a parallel port serial connection. I have Labview 2018 installed on Centos 7 along with nivisa. When I run "sudo NIvisaic" I can see the serial port but without sudo I can not (it shows as unknown). When using the port in lab view I get the error

"Error -1073807192 occurred at VISA Write in Parallel

VISA: (Hex 0xBFFF00A8) Access to the resource or remote machine is denied. This is due to lack of sufficient privileges for the current user or machine" 


running "sudo Labview64" shows command not available. How do I run labview with escalated permissions to see this port or is there something I am missing?

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Message 1 of 7

It's been a really long time since I used Linux, but can you go to the /dev/ directory and find the port you need to use (lp0 if it's really a parallel port, ttyS0 if it's serial, maybe something else newer...) and change the permissions there using sudo just once?

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Changing the permissions with "sudo chmod 666 /dev/parport0" doesn't seem to have helped. I also checked the permissions have properly been changed with "ls -la"

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Message 3 of 7

777? maybe?

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Message 4 of 7

No luck with 777 either. (im not sure if 777 should be used on device files, only difference is if they are executable)

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Message 5 of 7
Accepted by topic author TypT

Solution to run labview as root on centos 7:

install kdesu:

"sudo yum install kf5-kdesu"

run labview as root (from default install location):

"kdesu /usr/local/bin/labview64"


Enter the root password for the machine and labview should start running with escalated permissions.

If labview is installed in a different location you can find it with "which labview64"


"sudo /usr/local/bin/labview64" may work as well but it is not recommended to run GUI programs as root directly.

Message 6 of 7

Ick.  Thanks for sharing the solution with us, though.  This is bound to help someone.  🙂

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