Field Check Using Dm70 - Vaisala HUMICAP DMT132 User Manual

Chapter 5 ______________________________________________________________ Maintenance
NOTE
NOTE
VAISALA _______________________________________________________________________ 53

Field Check Using DM70

To check of the accuracy of the DMT132 in the field, you need the
following equipment:
- A fully charged MI70 indicator (the measurement display that is
included in the DM70 and HM70 hand-held indicator products)
- A calibrated reference probe that is suitable for the intended
measurement environment and dewpoint range.
- DMP74A probe from the DM70 is the recommended choice, as
it offers the best accuracy in the measurement range of the
DMT132.
- All probes compatible with the DM70 and HM70 hand-held
indicators may be used as a reference.
- You can also use a second DMT132 transmitter.
- A connection cable between DMT132 and the MI70 indicator (Vaisala
order code 219980).
- A reference environment with a stable dewpoint and temperature in a
suitable range for both devices. The normal measurement environment
of the transmitter can also be used, if it meets these criteria.
In the procedure below, the readings of the devices are checked
individually. You can also perform the field check so that you connect
the reference probe simultaneously with the DMT132 you are checking.
In this case, you need two of the connection cables if you are using a
DMT132 also as the reference probe.
Make sure that the measurements are made in the same pressure.
Perform the check as follows:
1. Place the DMT132 in the reference environment (unless it is
already). You can perform the check even if the DMT132 is
currently being powered and used, as long as there is no cable or
LED indicator plug connected to connector II. However, external
powering is not needed when using the MI70 indicator with
DMT132.
2. Connect the MI70 connection cable between the MI70 indicator
and connector II of the DMT132.
3. Turn on the MI70 indicator.
4. Check and adjust the environment settings if prompted. You can
only change the pressure compensation value that is used for
dewpoint temperature calculation.