Vaisala DMT143 - CALIBRATION AND ADJUSTMENT; Field Check Using the DM70 Hand-Held Dewpoint Meter

Procedure Instruction 13(16)
Field Tech Manual for DMT143-series
2018-04-06
Vaisala Instruments
CALIBRATION AND ADJUSTMENT
Calibration and Adjustment Overview
You can calibrate and adjust the transmitter using the following tools:
• Serial line commands
• Portable humidity meter HM70
Vaisala Service Centers also offer accredited calibrations dewpoint.
Field Check Using the DM70 Hand-Held Dewpoint Meter
Vaisala recommends the following equipment for field checking:
- A fully charged MI70 indicator (the measurement display that is included in the DM70
package).
- A calibrated reference probe that is suitable for the intended measurement environment
and dewpoint range. The DMP74B probe is recommended for checking the dewpoint and
temperature measurement accuracy.
- You also need a connection cable (Vaisala order code: 219980SP) to connect the DMT143
to the MI70 indicator.
NOTE In the procedure below, the readings of the transmitter and the reference probe are checked
simultaneously. You can also check the reference probe and the DMT143 separately if they cannot be
connected at the same time.
Perform the check as follows:
1. Place the reference probe and the DMT143 in the reference environment.
2. Connect the reference probe and the DMT143 to the MI70 indicator:
- Reference probe to Port I
- DMT143 to Port II
3. If you have altered the DMT143 serial port settings, switch off the other power supply (disconnect
“Analog” cable if in use) before powering up the MI70. Note that this powers off the transmitter, and it
will carry out the startup sequence (see section DMT143 Startup Sequence on page 20) when powered
on again.
4. Turn on the MI70 indicator. Never connect or disconnect the MI70 indicator while it is powered on, as
this may cause incorrect values to be displayed.
5. Check and adjust the environment settings if prompted. Refer to the DM70 User’s Guide for the
settings of the DMP74B probe.