Two-point temperature calibration and adjustment using computer - HMD110 - HMD112 - HMS110 - HMS112 - HMW110 - HMW112 - TMD110 - TMI110

You can also use Vaisala Insight software for performing calibration and adjustment. See Vaisala Insight software.

Computer with
- Windows operating system
- Terminal application
- Free USB port
- Driver for Vaisala USB cable installed
Vaisala USB cable for computer connection (219690)
Two temperature references in range -40 ... +60 °C (-40 ... +140 °F) with more than 30 °C (86 °F) difference
Medium size crosshead screwdriver (Pozidriv)

Prepare the HMDW110 series transmitter for a service port connection.
1. Open the cover of the HMDW110 series transmitter.
2. If the terminal block for terminals 5 ... 8 is wired, pull it out.
  This disconnects the transmitter from supply voltage and prevents possible equipment damage that may be caused by ground loops. The locations of the terminal blocks and the service port are shown in HMDW110 series component boards.
3. If the other terminal block is wired (terminals 1 ... 4), pull it out also.
  This prevents the communication between the transmitter and the Modbus (RS-485) host from interfering with your connection.
Plug in connection cable 219690 to the service port of the HMDW110 series transmitter, and the other end to a free USB port on your computer.
Insert the probe in the first temperature reference.
Wait at least 15 minutes for temperature to stabilize.
Start a terminal application on the computer and open a new terminal session to the transmitter. For more information, see Terminal application settings.
Give the errs and send commands to check that there are no active errors, and that the measurement is working:
```
errs
0000h
No errors
send
T= 23.1 'C RH= 11.5 %RH Td= -7.3 'C Tw= 9.9 'C h= 28.5 kJ/kg
```
Give the l command to view the currently active user adjustment parameters.
Example: Default values of the user adjustment parameters (no user adjustment done):
```
Cp offset : 0.00000000E+00
Cp gain : 1.00000000E+00
T offset : 0.00000000E+00
T gain : 1.00000000E+00
```
Give the ct command to start the calibration and adjustment sequence. The transmitter shows the measured T value and prompts you to enter the real temperature of the first reference point.
```
ct
T : 22.9424 1. ref ?
```
Press Enter to refresh the measured value (to see if the measurement is now stable). When it is, enter the value of the first reference point (in degrees Celsius) and press Enter.
```
T : 22.9424 1. ref ? <cr>
T : 22.9424 1. ref ? 23.0
Press any key when ready ...
```
To exit the procedure without adjusting the measurement, press the Esc key on your keyboard.
Transfer the probe to the second temperature reference.
Wait for the temperature to stabilize. Press Enter on the keyboard to refresh the measured value:
```
Press any key when ready ...
T : 54.9871 2. ref ? <cr>
T : 54.9873 2. ref ? <cr>
```
When the measurement is stable, enter the value of the second reference point and press Enter.
```
T : 54.9873 2. ref ? 55
OK
```
Give the l command to verify that new values for user adjustment parameters T offset and T gain have been stored.
Example: User adjustment parameters after two-point temperature adjustment (your values will be different):
```
Cp offset : 0.00000000E+00
Cp gain : 1.00000000E+00
T offset : 7.64255524E-02
T gain : 1.00767076E+00
```
Remove the probe from the temperature reference.
Update the calibration date and calibration information on the transmitter using the cdate and ctext commands.
Example: Set calibration date to 2018-07-04 and calibration info text to "Lab2/Mike".
```
cdate 20180704
Cal. date : 20180704
ctext Lab2/Mike
Cal. info : Lab2/Mike
```
Disconnect the connection cable from the service port.
Reconnect the terminal blocks and close the cover.

Two-point temperature calibration and adjustment using computer - HMD110 - HMD112 - HMS110 - HMS112 - HMW110 - HMW112 - TMD110 - TMI110 - TMW110

HMDW110 with TMI110 User Guide