Hi,

I'm using a word for various commands from WinCC unified HMI.

Each bit in this word is a "command" bit to the PLC.

Using .SetBitInTag(Tag, BitNo). The Tag (command word) is a part of an UDT.

The PLC will check each bit in the word, and set the command word to 0 immediately.

(Fire and forget seen from the HMI)

This is working as intended, except for the fact that the status of the bit is somehow stored as true in the HMI. This despite that the whole command word has been set to 0 by the PLC.

When monitoring the command word in the HMI and the PLC it is 0.

But if I do set a another bit in the command word, both the bits will then be set to true.

Only way to avoid this, is to wait 1s or more in the PLC before setting the command word to 0.

It does look like the Tag is in some kind of quarantine after using SetBitInTag, and are not detecting that the command word was changed by the PLC.

There is probably some event triggered on value change that is not detected in this quarantine period.

I'm also able to reset the bits when editin the command value from 0 to 0 in the HMI. This will probably trigger an on value change event internally.

Anybody that knows any good solution for this problem?

The problem is solved. I had an edit field of the command word in addition. When I deleted the edit field, everything worked as intended.

Hello. What do you mean by “I had an edit field of the command word in addition”, was that an input field or something? I have similar problem.