Vaisala HM70 User Manual

Page 54

User's Guide ______________________________________________________________________

52 __________________________________________________________________ M210297EN-E

the difference between two references is less than 50 %,
adjustment can not be done.

18. Adjustment is done. Press

BACK

to exit the adjustment mode

press

EXIT

to return to the basic display.

19. Replace the jumper to

CAL.RH

pins.

20. Switch off MI70 and detach the calibration cable from the MI70

and from the transmitter.

Calibration and Adjustment of HMT330 Series
Transmitters

You can check and adjust both humidity and temperature channels of
the HMT330. If you adjust both channels, make the temperature
adjustment first.

Calibrate your transmitter against a calibrated reference probe of
HM70 or against a calibrator's reference humidity by using MI70
indicator in communication. Follow the first 8 steps and continue
according to the chosen calibration method.

Connect the

211339

-calibration cable to the

SERVICE PORT

connector on the mother board of the HMP330.

Connect the other end of the calibration cable to either of the
HM70's connector port located on the bottom of the indicator,
see Figure 7 on page 40.

Turn on both devices.

The reading of the transmitter is shown on the first or middle
row of the display, depending on the connector port to which the
calibration cable is connected. Value of the port I is shown on
the upper row of the display and the value of the port II on the
lower row of the display. Difference of the readings is shown on
the lowest row.

If you have HMT330 with the optional chemical purge option,
you should activate the chemical purge before calibration and
adjustment. You can do this via the MI70 indicator: open the

MENU;

press

OPEN

select

Functions

, press

START

and

YES

Wait until the purge is complete before continuing with
calibration and adjustment.

Press the

ADJ

button (on the mother board of the HMT330) to

open the adjustment mode. The indicator led (on the
motherboard of the HMT330) starts flashing.