Vaisala HMP228 User Manual
Page 30
HMP228
Operating Manual
M210282en-A
24
•
Press any key and press
point value.
RH : 75.5 Ref2 ? yy.y
4.3.2.2
Using display/keypad commands
•
Make sure that the sensors of the transmitter and the reference
instrument are close to each other. Allow enough time for the sensors
to stabilize to the measurement conditions.
•
Select Cali in the main menu and then RH cal; select Not changed
and then one point offset calibration RH 1 point cal. Change the
humidity reading with the arrow keys to correspond the reference
humidity and press ENT; pressing an arrow once changes the reading
by 0.05 %RH.
4.3.2.3
Using LED commands
•
Make sure that the sensors of the transmitter and the reference
instrument are close to each other. Allow enough time for the sensors
to stabilize to the measurement conditions.
•
Connect an ammeter/voltmeter to the analogue outputs (connector
X2). If the outputs are already connected to e.g. a process computer
and you do not want to disconnect them, the current output can be
measured at separate test points located next to connector X15 (see
the mother board).Give command ¡¡¡l. At the first calibration
point the LED on the left flashes; adjust the humidity point (offset)
with the arrow switches to the reference value. One push of a switch
changes the output by 0.05 %RH; the change of the output voltage or
current depends on the output scaling. Press ENT switch. The second
LED from the left starts flashing; press ENT again.
4.4
Changing the moisture sensor
Remove the damaged sensor and insert a new one. Handle the sensor by the
plastic socket. DO NOT TOUCH THE SENSOR PLATE. After sensor change,
the moisture calibration must be performed according to the instructions in
section 4.4.1.