Siemens positioner failure
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Last night, during the night shift, the position of one pressure-controlled valve remained at 100. Upon arriving at the site, the Siemens locator panel indicated that the input signal was 0 (the signal provided from the control room); this meant the control valve should be in the fully closed position, yet the valve’s position indicator showed it to be fully open. In fact, the valve was indeed fully open on site. The air supply pressure to the locator was normal, but the locator’s output was at its maximum level. After the air supply was cut off, the valve closed completely and did not get stuck. After it was automatically adjusted, the locator worked properly (although the adjustment time was a bit long, especially for the first step). Subsequently, the valve functioned normally. I would like to ask the experts: where does the fault in the locator lie?
I’m sorry; the image is not very clear due to the lighting on site. This should be from the calibration process
Is Mo Ming having a seizure? :lol:lol:lol:lol
The investigation operator reviews the operation change records for that valve level
It’s so strange; just make a self-diagnosis and that’s it: lol
It seems that the positive and negative feedback of the valve positioner is being impaired
In such a situation, first measure the MA value on site; if it is 4MA and the valve shows to be fully open, then the action direction of the actuator is reversed, and it needs to be adjusted. But you said just adjust it, and then trouble arose!
The parameters inside the locator should be checked first; it’s the last step during self-testing.
Such issues can only be determined on-site; when a problem occurs, what is the current level at the site? Is the air pressure 5 kilograms, and is the valve position feedback resistor functioning properly?
In such a situation, it is first necessary to determine the valve positions corresponding to 4mA and 20mA at the site, and then check those in the control room to see if they match. In the case described by the poster, it is very likely that the values do not match; perhaps the operator in the control room made some changes earlier, and then changed them back after you carried out the adjustments
Thank you all for your advice. Next time, I will first measure the input current, then check the controller configuration, and finally discuss things with the control room to finalize everything