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Communication Driver Error (200)

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I have a problem on my Samba SM43-J-R20 PLC. I control a type of a filling machine with this PLC. The program works fine, all works like it should. But if I want to go online and observe what is happening, I frequently lose communication with PLC. Is it possible, that there is some electrical connection problem or some sort of short circuit that disables the connection?

I have attached picture of the error.

Thank you for your help!

Best regards, Marko!

Posnetek zaslona 2024-02-21 083231.jpg

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Hi Marko;


Are you using the   Unitronics USB Cable      USB2-CAB200?  This has a Ferrite on it to reduce noise in the line.

If not, use a cable with a Ferrite.

Normal COM settings are   115 k Baud, 8,n,1

Check your PC  Comprt settings -   Control Panel - Device Manager

Check Comport settings on the PLC  -- you can get this infor using     Info Mode

      Hold  non active touch are on screen for about 8-10 seconds

        follow prompts, - Enter Info Mode,  password ( default) is 1111

                 Serial Communications  - USB uses COM 1

    Try  communicating - there is a TX-RX   that will index with communications, also, you can monitor the com line


Keep cables away from VFD lines and power lines


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I may add to what @DanT say - USB cable should be certified for USB 2.0.

USB cables, supplied by Unitronics, are carefully tested, and tests include download of large projects, taking near 30 min or more, long test in online mode, and other tests.

Other cables may have NOT SCHIELDED, BAD SCHIELD, NOT TWISTED USB wires.

So if there are EMI or Ground Loop between PC/Laptop and PLC/Cabinet, you may face communication disconnects.

If you are working with Laptop - check if disconnecting power supply improve communication.


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