Instruction manual

Instruction Manual
760006-A
September 2001
Rosemount Analytical Inc. A Division of Emerson Process Management Appendices 11-7
Model NGA 2000 Platform
• Fixed on range 1
• Fixed on range 2
• Fixed on range 3
• Fixed on range 4
• Independent (i.e. may auto range
change or respond to range inputs, but
without affecting the Analyzer range)
Setting up alarm relays - V2.2
You can make the alarm relays respond
to concentration values, or to certain
status values. You can express concen-
tration values in absolute numbers, or as
a percentage of scale.
1. Select Expert controls and setup...
2. Select Auxiliary module setup...
3. Select the analog I/O module.
4. Select Alarm conditions...
5. Select a condition for each alarm
relay. In V2.2, Analyzer specific
alarms do not work (refer Table 11-2
for available alarms).
6. Go back one screen, and if you
have selected any concentration
alarms, select Concentration alarm
parameters...
In this screen, Trips as % of range or
absolute: is whether to alarm as per-
centage of range or on absolute val-
ues. If the former, the alarm set point
will change with each range. If the
latter, there will be a single alarm
point, no matter what range is se-
lected.
7. Select Hysteresis:. This is the differ-
ence between the “on” point and the
“off” point, expressed as a percent-
age of the on point. E.g., in the case
of a high alarm, if the alarm is set at
80ppm, it will trip when the reading
goes above 80ppm. When it comes
back down if the hysteresis is set to
10%, the alarm won’t go back off
until the reading gets below 72 ppm.
The 10% default is usually satisfac-
tory.
8. Select the Delay till alarm actuates:
This adds a time delay, preventing
nuisance alarms on short term
spikes in the reading.
9. Set the alarm level in either absolute
or percentage of range. You can
select both, and then the alarm set
point will perhaps change as you
select whichever mode you want.
10. Select Alarm type:, as high or high
high, or low or low low. High high
goes off at a higher value than high,
but it doesn’t matter if you get it
wrong.
11. Select Alarm operation:, fail-safe or
not. Fail-safe means that the relay is
IO module ID: