4.9 Devices and transmitters for measurement of differential pressure shall be calibrated either:
a) at atmospheric pressure on a disconnected measuring line by means of an etalon device. Calibration shall be done not less than at five points of the measuring scale, ascending and descending from minimum to maximum. After the unit is returned to operation, its “zero” point shall be reset under operating pressure.
Я понимаю выражение "reset to zero point", а как можно переустановить сам нуль? или я что-то не поняла..
Спасибо!