The influence between zero adjustment and range adjustment in PLCs
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The unit uses a PLC system; does zeroing the pneumatic control valves on site have an impact on the range?； Also, does adjusting the range separately have an impact on the zero point?
Nonsense upstairs. . . . . . . . . . . . . . . . . . Identification completed. . . . . . No explanation
Adjusting the zero point has little effect on the range, while adjusting the range has a much greater impact on the zero point.
The PLC system and the field are two separate control units; generally, the output of an AO card will not cause any problems unless it is damaged. As for the valve positioners at your site, if you have adjusted their zero point, it is recommended that you also check their range.
The control valve adjusts the zero point and range, following the adjustment principles of the positioner; it has nothing to do with the PLC.
On-site calibration does not affect the PLC; whether the on-site locator has its zero point or range adjusted, it is ultimately the PLC that provides the signal to verify the valve position. The zero point and range of the locator sometimes need to be adjusted repeatedly.
Regardless of the type of control system in use, the adjustment of the valve’s zero point and range has nothing to do with it. The valve simply receives a standard 4–20 milliamp signal from the system; its zero point and range can be adjusted by modifying the valve positioner. With mechanical positioners, it is necessary to determine the balance point first before repeatedly setting the zero point and range. However, many modern intelligent positioners do not see as much influence from these factors