Martek Instruments Mark 25 - Calibrating Conductivity

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3.4 Calibrating Conductivity
Calibrating conductivity follows the
same procedure as the temperature
calibration. However, if the Mark 25 is
not set up for auto-ranging prior to
conductivity calibration, 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> key until CON is
flashing. Follow the same procedure for
zero calibration for conductivity that was
used for temperature.
To span conductivity, press the
<CALIB> key and select the conductivity
prompt. Next, press the <UP ARROW>
key when the Aut prompt is displayed.
The Mark 25 will display the calibration
bars then briefly display 1.000 (or 10.0
or 100.0 depending on the range
previously selected) 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 any parameter
on any channel.
Press the <CALIB> until the display
indicates the alarm prompt, ALA. Next,
press the <UP ARROW> key. The
display will prompt with AL 1 and all
parameter LED’s will be lit. The <UP
ARROW> key can 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 display three bars. The bars indicate
no alarm set point. Use the <UP> or
<DOWN ARROW> keys to select
temperature (t), raw conductivity (rc), or
temperature-corrected conductivity (tc).
Press the <CALIB> key to select the
desired parameter.
The Mark 25 will then display Lo. To
select a low set point, press the
<CALIB> key. If a high alarm set point is
desired, use the <UP> or <DOWN
ARROW> key to change the display to
hi then press the <CALIB> key to
select.
The Mark 25 will display .000 (if raw or
temperature-corrected conductivity is
selected) though the decimal point may
vary depending on the range previously
selected.
Use the <UP> or <DOWN ARROW>
key to 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.