Problem with opening of automatically controlled valves in WINCC
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In the WinCC interface, valves have three buttons: open, close, and force. After one year of use, the opening button fails to properly open the valve; a forceful click is required to open it. Since these are all pneumatic valves, can it be understood that when the command to open the valve is issued, the PLC sends out signal 1, compressed air is supplied, signal 1 is sent back, and then the PLC issues another signal to open the valve? Forced execution directly outputs the open signal, skipping the aforementioned process.
As long as it is controlled by a PLC, the following steps must be carried out: \"PLC outputs signal 1, compressed air is supplied, signal 1 indicating that the valve is open is sent, and the status of the open valve is displayed on the upper-level computer.\"
The key is to figure out what each of those three buttons was used for back then
It depends on how the backend program is written and how the screens are linked; it has nothing to do with WinCC itself, as the screens in WinCC are created by the user.
If nothing goes wrong, there might be an issue with the feedback line
First of all, the way you phrased your question is problematic. “The valve has three buttons: open, close, and force. After one year of use, the activation button fails to properly open the valve. ” What exactly does \"normally opening the valve\" mean? You need to describe it in detail: is it the case that the button cannot be pressed, or that pressing the button results in no output from the DO terminal, or that the DO terminal does output a signal but the valve doesn’t move, or that the valve moves but there is no feedback? It’s meaningless to seek help online when you can’t even describe the specific situation clearly as someone who was there. If it was normal in the 21st year but abnormal a year later, it is most likely a hardware issue. As for whether it is due to a chain signal preventing the valve from being opened or some other issue, this needs to be determined based on the actual conditions on site. If you are not from this field, it may be difficult to organize the language properly; it is recommended to have someone with expertise in instrumentation and automatic control come to the site to conduct an inspection.
The presentation is highly professional, enabling those who are not familiar with the topic to quickly understand how to analyze problems – truly impressive
Based on your description, I can only guess that the buttons for turning on and off belong to a valve control function block, while the ‘force’ option likely involves connecting the button directly to a DO point. If using the force function works and the valve operates properly, then there are no issues with the wiring, DO cards, or the valve itself; in that case, the problem lies with the function block. Function blocks generally require connection to valve position feedback. If it’s a pneumatic valve, that is, one controlled by a solenoid valve, then it’s usually the correctness of this valve position feedback that affects the output of the function block. You should focus your checks on this aspect. Another possibility is that the program has been altered, including the configuration settings in WINCC; if the configuration of the upper-level interface is incorrect, it will be impossible to trigger the opening and closing of the valves.