Support Needed: Writing STRING Tags on Omron NX1-9000 Using libplctag.NET

[S Pozzebon]

Hello,
I’m currently working on integrating an Omron NX1-9000 PLC with a Windows (.NET) application. For this purpose, I’m using the libplctag.NET library, which is free and open source. 

The communication is set up correctly, and I’m able to read and write tags of type Integer, Real, and Boolean without issues. However, I’m having trouble writing to STRING tags.

Specifically, I can successfully read the content of STRING tags, but writing new values doesn’t work the data either isn’t updated in the PLC or is written incorrectly.

I suspect this could be related to how different PLCs handle string encoding, length information, or terminators. Still, I’m not ruling out the possibility that I’ve misconfigured something in the tag definition or communication setup.

I’m reaching out to ask if anyone has had a similar experience using libplctag.NET with Omron NX PLCs, or if there’s any specific documentation or best practice for handling STRING tag writing.

Any help or suggestions would be greatly appreciated.

Best regards,

Simone Pozzebon

[Kyle]

See the issue about this that was recently closed.  The defaults for OMRON strings are not correct. Unfortunately, it does not look like there is a single default that will work for single strings and arrays of strings.

Let me know if that works for you.  You will need to translate the tag string attribute names for use with libplctag.NET.  Usually you just capitalize each word and remove the underscore characters.

Best,

Kyle