Please help MODBUS is showing error -1073807246 and its COM is used by some unknown process

[Sachin_girdhar]

please let me know how I can free that Com port so that it can be used for modbus... I am using VISA CLOSE Function, but I think some unknown process taking the handle of that com port continuously.

[RavensFan]

Close other programs you have running.  Have you possibly opened some communication software that came with the device you are trying to talk with?

If that doesn't work, reboot your PC and try using it again before you work with any other programs.  Something is opening it and failing to close it.  It's just a matter of figuring out which program is doing that.

[Himanshu_Goyal]

Hello Sachin

This error most often occurs when you try to open a VISA Session to a resource that already has been opened. (In serial communication, this is not allowed, and subsequently causes this error). Be sure to close all sessions in your code.

Before post any query first try yourself to resolve it. If not able to resolve than only post the query. You have the error code -1073807246 servh this in search box this will search all the discussion and solutions related to this,

[Prabhakant_Patil]

Please fo thorugh following link,

It will help you, for the modbus communication.

https://forums.ni.com/t5/Reference-Design-Content/LabVIEW-Modbus-API/ta-p/3524019

https://www.ni.com/en/support/downloads/tools-network/download.modbus-master.html

Prabhakant

[Himanshu_Goyal]

Hello Prabhakant,

All above mention links are related with the ModBUS library. I think discussion is about the error, If engineer getting the error it indicates that he already have the ModBUS library and while executing the code he is faceing some issues.