PPM–400ST Formaldehyde Meter Operation Manual
on screen.
3. Press the
$
button to navigate down to the setting
listed as
SP:At
, note the value (e.g. 1.4 seconds) and
change it to 20 seconds (you may only be able to
select 10 seconds depending on the age of the
instrument).
4. Continue to press
$
to navigate through the rest of
the menu system until the instrument switches off.
Now that the pump run time has been increased,
simply place the Sensor Refresh Standard over the
brass nozzle of the PPM–400ST and take several long
samples. You may need to repeat this procedure
depending on how low the Time-to-Peak Value is.
Once completed you will need to return the
instrument pump setting back to the original value
noted in Step 3 above and recalibrate the PPM–
400ST.
If the instrument is still displaying this message,
please contact PPM Technology for further help.
Checking
Calibration Gain
1. Hold down the
<
button whilst turning the
instrument on.
GAIn
will appear on the display.
Release all the buttons.
2. A four-digit value will alternate with a two-digit
exponent on the display:
4321
and
1E:17
, for example.
3. Make a note of both numbers. The instrument will
turn off after a few seconds.
If the Exponent value is between
1E:15
and
1E:13
then
you may have used an expired Calibration Standard –
check your Calibration Standard expiry date.
If the Exponent value is less than
1E:13
you may have
accidentally calibrated without a Calibration
Standard being present.
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