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43-TV-25-11 GLO Issue 11 03/02 UK
Alarms allocated to a pen can be graphed using Maths.
“Maths” on page 18 and
“Appendix A - Maths Expressions” on page 73.
Alarm Controls
To add an alarm select
New
, this will automatically be assigned a name. The
De-
lete
alarm button removes the currently selected alarm from the list.
Enabling Controls
Enable as
Always
makes the alarm always active, continually checking and ready
to be triggered.
The
By Digitals
option is only available if the recorder has an alarm card fitted
which has the digital input/output function. It is necessary to setup the digital I/O card
before this option shows as available. To configure the digital I/O, click on the Hard-
ware Button to add a alarm card with digital I/O capability (if fitted in the unit as an
option). See
“Digital input/output port setup” on page 23.
By Digitals
enables the alarm if one of the digitals has en-
tered its specified state determined by the Digital Inputs button.
This button activates a list where by the available digital inputs
can be added or removed to the list of triggered alarms.
The
Disable
digital is its default state and if selected, the alarm will appear in the
recorders alarm list but will not be active.
Click in any area on the screen and press F1 on the keyboard to display the related
help files.
General alarm settings
Select the
Type
of alarm, either
High
or
Low
so if the level goes above the stated
value, on a high alarm, or below the stated value, on a low alarm, the alarm will be
triggered.
Log mode
is set to
Normal.
Set the alarm
Level
by entering the numeric
value at which the alarm is to be activated, the level is in terms of pen units so must
not exceed the current pen scale. If the alarm is required to be logged to disk then tick
Log as Event
. Tick
Mark on chart
if a marker is required to be placed on the chart
when an alarm is triggered.
Choose whether to
Trigger relays on alarm entry,
tick this to produce the Relay Outputs button. Select
relays from the
Relay Output
list and add to Trigger
Output list using the
Add
and
Remove
buttons.
Advanced options
Hysteresis gives the alarm a tolerance level. It allows a specified percentage value
of the full scale to be added on to the alarm level. The
Symmetrical
option divides
the hysteresis value equally on either side of the alarm. If the Hysteresis value was
10%, and the symmetrical option is enabled, then the logged reading would trigger at
5% (of the full scale value) below the alarm level. For the alarm condition to end, the
alarm would have to rise to over 5% (of the full scale value) above the alarm level.
Damping
With this enabled, an alarm level must be breached for a specific period of time
before an alarm is triggered. Enable this function and enter a time limit here, in hours,
minutes and seconds with a maximum time of 12 hours.