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TCD Analyzer
The concentration alarms can be configured from the display as
either high or low alarms by the operator. The alarm modes can be set as
latching or non-latching, and either failsafe or non-failsafe, or, they can
be defeated altogether. The setpoints for the alarms are also established
using this function.
Decide how your alarms should be configured. The choice will
depend upon your process. Consider the following four points:
A. Which if any of the alarms are to be high alarms and which if
any are to be low alarms?
Setting an alarm as HIGH triggers the alarm when the
concentration rises above the setpoint. Setting an alarm as LOW
triggers the alarm when the concentration falls below the
setpoint.
Decide whether you want the alarms to be set as:
Both high (high and high-high) alarms, or
One high and one low alarm, or
Both low (low and low-low) alarms.
B Are either or both of the alarms to be configured as failsafe?
In failsafe mode, the alarm relay de-energizes in an alarm
condition. For non-failsafe operation, the relay is energized in
an alarm condition. You can set either or both concentration
alarms to operate in failsafe or non-failsafe mode.
C Are either of the alarms to be latching?
In latching mode, once the alarm or alarms trigger, they will
remain in the alarm mode even if process conditions revert to
non-alarm conditions. This mode requires an alarm to be
recognized before it can be reset. In the non-latching mode, the
alarm status will terminate when process conditions revert to
non- alarm conditions.
D Are either of the alarms to be defeated?
The defeat alarm mode is incorporated into the alarm circuit so
that maintenance can be performed under conditions which
would normally activate the alarms.
The defeat function can also be used to reset a latched alarm.
(See procedures, below.)
If you are using password protection, you will need to enter your
password to access the alarm functions. Follow the instructions in
Teledyne Analytical Instruments
Operation
81
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