Micromod MOD: 30ML Operation and Template Setup - Manual (Page 51)

MOD 30ML Multiloop Controller
OPERATION
3-19
3.13 ALARMS
Alarm conditions are indicated on the front panel visually by an alarm light and audibly by a
beeper. Various combinations of audible and visual alarm indication can be obtained by
configuration. Alarm data can be viewed on a dedicated alarm display provided for each
active alarm.
Alarms can be configured for each control loop to respond to an alarm condition on the
process variable, the control output, and the deviation between the set-point and process
values. As many as four process alarms and two each of the deviation and output alarms can
be configured for each control loop. Alarm types can be high, high high, low, low low, and a
digital output can be enabled for each alarm. The parameters of any of these alarms can be
adjusted in the Tune mode. Tuning allows the following:
• Adjustment of trip value
• Adjustment of hysteresis value
• Assignment of a priority
• Suppression of a configured alarm
Other alarms are available as follows:
• The instrument provides an alarm indication for all diagnostic events which occur in each
configured control loop. Parameters of these alarms are not tunable.
• Data quality alarms can be configured to provide an indication of bad quality on the
process, remote set-point, and feed forward inputs. Priority is the only tunable parameter
for quality alarms.
3.13.1 Alarm Trip points
The high and low alarm trip-points for each control loop are determined at the time of setup.
The trip points and other parameters can be adjusted in the tune mode (see Section 3.14
Tuning). Process and deviation alarms are triggered by the process input. A process alarm
trips (becomes active) when the process reaches a preset high or low trip-point. A deviation
alarm trips when the process value deviates from the control loop set-point by a preset
amount. An output alarm is activated when the control loop output reaches a preset high or
low trip-point. Alarms resulting from rising values are defined as high, and those resulting
from falling values are defined as low. The terms high high and low low mean that two
separate alarms are configured on a single variable with either two high or two low trip points.
3.13.2 Alarm Priority
A priority (0 to 255) can be assigned to each alarm. Alarm priorities are used to display a
more important alarm before a less important alarm when viewing the alarm displays. Priority
1 is the highest priority and priority 255 is the lowest. Priority 0 is assigned to alarms which do
not require acknowledgement; these alarms can only have an active or clear condition.