
6. Verify that the connection works by giving the
?
command.
?
If the probe does not respond with device information:
• Disconnect the USB cable from the probe and retry. If your probe is in the analog
output mode, press
ENTER
a few times immediately after connecting the USB cable.
• Try the
??
command in case the probe is in POLL mode, open the line using the
OPEN
command if necessary.
• Check your serial line settings and cable connections.
7. When your serial connection is working, use the
L
command to see the current user
adjustment parameters.
l
8. Use the
ERRS
command to see that no errors are active.
errs
9. Use the
SEND
command to verify the currently measured RH value.
send
T= 22.9 'C RH= 11.1 %RH Td= -8.0 'C
10. Give the
CRH
command with the RH value of the humidity reference as a parameter.
crh
11
OK
11. After entering the correction, unplug the USB cable from the probe. Insert the probe in
the NaCl salt chamber (75 %RH) and wait for 20 … 40 minutes for humidity and
temperature to stabilize.
12. Connect the USB cable to the probe and use the
SEND
command to see the currently
measured value.
13. Give the
CRH
command with the RH value of the humidity reference as a parameter.
crh
75
OK
14. Check with the
L
command that the user adjustment parameters have changed. If you
wish to remove the effects of RH calibration (returning the RH measurement of the probe
to the factory calibrated state).
Chapter 7 – Maintenance
59