How to perform online tuning of Siemens positioners?
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Could some expert please advise me on how to replace a Siemens positioner online? In one of our air separation units, the positioner of the reflux valve in the cyclic nitrogen compressor has an output variation of around 10%; even slight adjustments to the valve cause significant fluctuations. Moreover, the LCD display shows large variations across the entire range of motion, although the actual valve does not experience such large fluctuations. This situation severely affects the operation of the unit. Currently, the positioner is fixed in place using clamps. Does anyone know how to replace a Siemens positioner online?
It cannot be changed online; even if you try to do it, the locator hasn’t been calibrated yet and therefore cannot be used. It’s better to address this issue when the machine is stopped
If it doesn’t cause any problems in the short term, a pressure regulator can be used to adjust the air supply – connect the air supply directly to the inlet of the valve, and use the pressure regulator to make the adjustments. Then install the locator, and switch back to the setting value.