Error "Bad_Failure" when writing empty string to tag in Ignition

Hi everyone,

I'm encountering an issue in Ignition SCADA when writing an empty string ("") to a tag. After running my script, the tag value updates to an empty string as expected, but I still get a "Bad_Failure" error popup. Here are the details:

Error writing "" to tag [Default]TestCompany/ML/A3/ObjID_Des Bad_Failure

  • Tag Path: [Default]TestCompany/ML/A3/ObjID_Des
  • Error Message: Error writing "" to tag [Default]TestCompany/ML/A3/ObjID_Des Bad_Failure
  • Script Behavior: My script sets ObjID_Des to "". The tag value updates correctly, but the error persists.
  • Tag Configuration:
    -- Access Rights: Read_Write
    -- Tag Quality: Good
    -- Data Type: String
    -- OPC PLC Settings: Confirmed that the PLC allows writing empty string values
    -- Security: Configured to allow Read_Write for anyone
    What I've Tried:

Verified that the tag is writable and has no security restrictions.
Checked the OPC server connection, which is stable.
Confirmed the PLC accepts empty strings for this tag.

Questions:

  • Why does writing an empty string trigger a Bad_Failure error even though the tag updates correctly?
  • Is there a specific configuration in Ignition or the OPC server I should check to allow empty string writes without errors?
  • Could this be related to the tag's OPC item settings or a bug in Ignition?

Thanks in advance!

Is this a third party OPC server or Ignition OPC UA + driver? If Ignition, which driver? What’s the OPC Item Path of the tag?

What if you write an ASCII 0x00, does it error?

Sorry for getting back to you late! Here’s the image with the tag properties. I’m still figuring this out, so if you have any questions, just let me know!


Set the logging level for the com.inductiveautomation.ignition.gateway.opcua.client.connection.OpcUaConnection logger(s) to DEBUG and then try the write again. Afterwards see if there is an error in the gateway logs.