Two-point humidity calibration and adjustment using computer and HMK15 Humidity Calibrator - HMS110 - HMK15 - HMW112 - TMI110 - HMS112 - HMD110 - HMW110 - HMD112

HMDW110 with TMI110 User Guide

Document code
M211726EN
Revision
E
Language
English (United States)
Product
HMS110
HMW112
TMI110
HMS112
HMD110
HMW110
HMD112
Document type
User guide
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)
  • Vaisala HMK15 Humidity Calibrator with LiCl (11 %RH) and NaCl (75 %RH) salt solutions prepared.

    Other solutions may be used, but the difference between the two points must be ≥ 30 %RH. Additionally, one solution must be < 50 %RH, and the other must be > 50 %RH.

  • Medium size crosshead screwdriver (Pozidriv)
If you have changed the HUMICAP® humidity sensor of the transmitter, perform the procedure below so that you use the FCRH command instead of the CRH command.
  1. 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.
  2. 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.
  3. Remove the filter on the probe. This exposes the sensors to damage, so handle the transmitter carefully.
  4. Unplug the Ø12 mm hole on the LiCl (11 %RH) salt jar and insert the probe.
  5. Wait at least 15 minutes for humidity to stabilize. Stabilization may take much longer if there are temperature differences or the salt solution is freshly made.
  6. Start a terminal application on the computer and open a new terminal session to the transmitter. For more information, see Terminal application settings.
  7. 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
  8. 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
  9. Give the crh command to start the calibration and adjustment sequence.
    The transmitter shows the measured RH value and prompts you to enter the real humidity of the first reference point.
    crh
    RH : 11.5378 1. ref ?
  10. 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 and press Enter.
    RH : 11.5378 1. ref ? <cr>
    RH : 11.5379 1. ref ? <cr>
    RH : 11.5379 1. ref ? 11.3
    Press any key when ready ...
    To exit the procedure without adjusting the measurement, press the Esc key on your keyboard.
  11. Transfer the probe to the NaCl (75 %RH) salt jar. Plug the hole on the LiCl (11 %RH) jar.
  12. Wait for the humidity to stabilize. Press Enter on the keyboard to refresh the measured value:
    Press any key when ready ...
    RH : 74.6984 2. ref ? <cr>
    RH : 74.7173 2. ref ? <cr>
  13. When the measurement is stable, enter the value of the second reference point and press Enter.
    RH : 74.9684 2. ref ? 75.4
    OK
  14. If the adjustment is successful, the transmitter responds with the text OK, and stores the adjustment.

    If the reference points do not fulfill the requirements, or the measurement is too unstable for adjustment, the adjustment sequence will exit with an error message. In such a case, the adjustment is not stored.

  15. Give the l command to verify that the values of the adjustment parameters Cp offset and Cp gain have changed.

    Example: User adjustment parameters after two-point humidity adjustment (your values will be different):

    Cp offset : -2.21914053E-03
    Cp gain : 1.00767076E+00
    T offset : 0.00000000E+00
    T gain : 1.00000000E+00
  16. Remove the probe from the salt jar and reconnect the filter. Plug the hole on the salt jar.
  17. 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
  18. Disconnect the connection cable from the service port.
  19. Reconnect the terminal blocks and close the cover.