Vaisala DMT132 - Manual (Page 60)

USER'S GUIDE____________________________________________________________________
58 __________________________________________________________________ M211289EN-A
Temperature Calibration and Adjustment
(CT)
The procedure below describes a temperature (T) measurement
calibration and adjustment using serial line commands. You can use the
procedure to do a one-point calibration (offset) or a two-point calibration
(offset and gain). For two-point calibration, the second reference point
must be at least 20 ºC warmer than the first.
1. Disconnect the cable from connector I of the DMT132 (if
connected).
2. Connect the USB cable to connector II on the DMT132, and to a
USB port on your PC.
3. Start a terminal application and set the service port connection
settings (19200 8 N 1). Remember to check which COM port the
USB cable is using.
4. Verify that the connection works by giving the ? command:
>?
If the transmitter does not respond with device information:
- Check your serial line settings and cable connections
- Reconnect the USB cable, restart the terminal application, and
try again.
5. When your serial connection is working, use the L command to see
the current user adjustment parameters. Write down the T offset
and gain values so you can restore them manually using the LI
command, if necessary.
>l
6. Use the ERRS command to see that no errors are active:
>errs
7. Insert the transmitter in the temperature reference.
8. Give the CT command. The output from the command shows the
currently measured T value, and prompts you to enter the value of
the first reference (Ref1). This is the reference on the colder end,
which produces the offset correction for the measurement.
>ct
T 21.0947 Ref1 ?