Vaisala PTU300 - Manual (Page 163)

Chapter 7 ____________________________________________________ Calibration and adjustment
VAISALA _______________________________________________________________________ 161
CHAPTER 7
CALIBRATION AND ADJUSTMENT
The PTU300 is fully calibrated and adjusted as shipped from factory.
Typical calibration interval is two years. Depending on the application it
may be good to make more frequent checks. Calibration must be done
always when there is a reason to believe that the device is not within the
accuracy specifications.
When defining the calibration interval the long term specifications and
the requirements of the customer must be taken into consideration.
Contact Vaisala Service Centers for details.
It is recommended that calibration and adjustment should be carried out
by Vaisala. For contact information of Vaisala Service Centers, see
www.vaisala.com/servicecenters .
Calibration and adjustment is carried out either by using the push buttons
on the motherboard, through the serial port or with the optional
display/keypad.
Vaisala portable instruments HM70 and HMI41 can also be used.
Pressure
The user can select a simple offset or a two-point offset and gain
adjustment and use the LCI command for adjustment of pressure
transducer. The MPCI command is used for the more sophisticated
multipoint correction capability at up to eight pressure levels.
Check first what linear corrections the transmitter is currently using
before attempt to readjust the transducer. As the previous linear
corrections will disappear when new linear corrections are input, the user
has to take into account the previous linear corrections when deciding
about the new ones.
NOTE Entering new linear or multipoint corrections will always cancel the
previous corrections. It is advisable to write down the previous linear
and multipoint corrections so that they will not be lost by mistake.