Adjusting the zero point is important when high accuracy is required.
The zero point signal of a pressure transmitter can shift:
- when it is installed, because of the mounting position or mechanical strain on the pressure connection,
- in operation, because of temperature changes,
- over a long time, because of aging.
Long-term stability (the maximum signal drift per year) is a quality parameter which must be specified in the data sheets.
When, how often?
If high accuracy is required,
- adjusting the zero offset signal during commissioning, after the instrument has been installed
- and subsequently according to requirements (e.g. every 12 months).
For certain installations, such as in power plants, regulations demand a documented check of the zero offset signal.