FISHER locator micro-fluctuation issue.
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The anti-surge valve we are using on site has a FISHER DVC6030 actuator, and it is a butterfly valve. During the valve calibration process, when a signal was sent to the valve, there were slight fluctuations at several opening degrees below 10%. The airtightness of the valve’s air supply system was checked and found to be fine; this issue did not occur during previous calibrations. It appeared this time, and the valve moved 2-3 times, with the point of fluctuation varying each time. I would like to ask the experts: what could be the cause of this? How should this be solved?
We have never used Fisher’s valve positioners; we use Yaskawa’s positioners instead. If surging occurs, self-tuning usually takes place, and once the tuning is complete, the surging stops. You can give it a try~~
It might be that the resistance of the butterfly valve itself has increased
The packing is too tight, or as mentioned above, the valve resistance is too high
This valve has been in use continuously, so it’s unlikely that the packing is tight. But still, thank you, haha! :)
:) There is an option in the Fisher locator menu related to damping, which can be adjusted to reduce sensitivity.
1. Adjust the opening and closing speed of the valve; slow it down a bit. 2. If there is a dead zone, increase it a bit. Some have them, while there are some dead zones that cannot be set
Make an online correction; if there are still issues, it’s the damping coefficient. To be specific, were the valves and positioners newly installed, or were they not of this type before?