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3.4 Calibrating Conductivity
Calibrating conductivityfollows the
same procedure as the temperature
calibration. However, ifthe Mark 25 is
not set up for auto-ranging prior to
conductivitycalibration, the desired
range must be selected (for information
on auto-ranging, see section 3.10 Auto-
ranging).
Press the <CALIB> key, then the
<DOWN ARROW> keyuntil CON is
flashing. Followthe same procedure for
zero calibration for conductivitythat was
used for temperature.
To span conductivity, press the
<CALIB> keyand select the conductivity
prompt. Next, press the <UP ARROW>
keywhen the Aut prompt is displayed.
The Mark 25 will displaythe calibration
bars then brieflydisplay 1.000 (or 10.0
or 100.0 depending on the range
previouslyselected) before returning to
the monitor mode.
NOTE: If the auto-ranging function is
OFF and the Mark 25 is monitoring raw
or temperature-corrected conductivity
and the measurement exceeds the
current selected range, the Mark 25 will
display Err. The decimal point will
indicate the range previously selected. If
an error message occurs, you must
select a higher range.
3.5 Setting Alarms
The Mark 25 has four alarm set points
that can be assigned to anyparameter
on anychannel.
Press the <CALIB> until the display
indicates the alarm prompt, ALA. Next,
press the <UP ARROW> key. The
displaywill prompt with AL 1 and all
parameter LED’s will be lit. The <UP
ARROW> keycan be used to change
the alarm set point to 2, 3, or 4.
To assign a particular alarm set point,
press the <CALIB> key. The Mark 25
will displaythree bars. The bars indicate
no alarm set point. Use the <UP> or
<DOWN ARROW> keys to select
temperature (t), rawconductivity(rc), or
temperature-corrected conductivity(tc).
Press the <CALIB> keyto select the
desired parameter.
The Mark 25 will then display Lo. To
select a lowset point, press the
<CALIB> key. Ifa high alarm set point is
desired, use the <UP> or <DOWN
ARROW> keyto change the displayto
hi then press the <CALIB> keyto
select.
The Mark 25 will display .000 (ifrawor
temperature-corrected conductivityis
selected) though the decimal point may
varydepending on the range previously
selected.
Use the <UP> or <DOWN ARROW>
keyto change the value to the desired
alarm set point. When the desired set
point is reached, press the <CALIB> key
to set and activate alarm.
NOTE: For convenience, pressing the
<RANGE> key will advance the digit left
of the decimal point.
To disable alarm, return the set point
value to .000.
Once an alarm set point has been
assigned to a particular parameter on a
channel, it cannot be assigned to
another parameter or channel until it
has been disabled.