10
When the Mark 25 reaches an alarm
state, the Alarm LED will light and the
alarm relay activate. The factory-set
position for the alarm relays is
NORMALLY OPEN. To change to a
NORMALLY CLOSED position, contact
Martek Instruments.
NOTE:
The Alarm LED will blink if there
are active alarms that are not being
viewed and will remain steady if the
channel viewed is in an alarm state.
3.6 Setting Recorder Outputs
The Mark 25 comes standard with four
4-20 mA analog recorder outputs and
one RS232 digital output. Like the alarm
set points, the four analog recorder
outputs can be assigned to any range of
any parameter on any channel.
Press the <CALIB> until the display
indicates the recorder prompt,
rEC
.
Next, press the <UP ARROW> key. The
display will prompt with
ou 1
and all
parameter LED’s will be lit. The <UP
ARROW> key can be used to change
the recorder output to 2, 3, or 4.
To assign a particular analog output,
press the <CALIB> key. The Mark 25
will display three bars. The bars indicate
no analog output assigned. Use the
<UP> or <DOWN ARROW> keys to
select temperature (
t)
, raw conductivity
(
rc
), or temperature-corrected
conductivity (
tc
).
NOTE:
A decimal point will be present
for
rc
and
tc
which indicates what range
these parameters are currently using. If
the auto-ranging function is ON, the
decimal point can be moved by pressing
the <RANGE> key.
Press the <CALIB> key to select the
desired parameter.
At this point, the standard 4-20 mA
output range can be changed to any
value desired. In addition, a “balance” is
provided to “fine-tune” each end of the
recorder range.
To change the lower end of the recorder
range, press the <ZERO> key. The
Mark 25 will display
4.00
. Use the <UP>
or <DOWN ARROW> key to change the
number to the desired value. When the
desired value is reached, press the
<CALIB> key to set the value in
memory.
At this point, the Mark 25 will then
display
000
. This is the “balance”. Use
the <UP> or <DOWN ARROW> key to
change the value in order to make the
lower end of the recorder range to agree
with the external recorder. When the
desired balance is reached, press the
<CALIB> key to set the value in
memory.
The same procedure is used to change
and “balance” the upper range of the
recorder output.
To disable any assigned analog
recorder output, select the particular
output and press the <CALIB> key.
Once the parameter is displayed, use
the <UP> or <DOWN ARROW> keys
until three bars are displayed. Press the
<CALIB> key to disable the output.
Once a recorder output has been
assigned to a particular parameter on a
channel, it cannot be assigned to
another parameter or channel until it
has been disabled.
NOTE:
When the auto-ranging function
is OFF, changing a conductivity range
with an assigned analog output
automatically changes the scaling of the
