Measurement Computing TempScan/1100 - Manual (Page 77)

TempScan / MultiScan User's Manual 879596 System Configuration 4-19
Alarm Configuration
The TempScan/1100 or MultiScan/1200 unit can be programmed to produce an internal alarm event when
the value of a channel is outside of user-defined limits. In turn, these alarm events can be used as sources
for Trigger or Stop events, or as stimuli for TTL-level signals. To use the alarms, the relevant channels
must be part of the channel scan. After an acquisition has been configured and armed, the alarms will be
enabled and monitored. Since alarming is totally independent of buffered operations, the assignment of
trigger events or scan intervals is not required.
Note: To enable alarm monitoring prior to, or have an alarm condition serve as, the Trigger or Stop
event, you must first configure the acquisition with at least one Pre-Trigger scan.
Alarm Setpoints
Each channel has an associated high and low setpoint. Setpoints are defined as part of a channel
configuration using the Configure Channels (
C ) command. These setpoints create the “envelope” that
constitutes the normal channel operating range.
If the channel value goes above the high setpoint or below the low setpoint, then the channel is in the alarm
state. If any configured channel is in the alarm state, a system alarm event will be posted. In turn, if the
Trigger event source is set to Alarm, this system alarm event would cause a Trigger.
Alarm Hysteresis
To avoid threshold transition problems, a hysteresis value can also be programmed. . A hysteresis value
provides a range for the alarm state. After the alarm setpoint is exceeded, the signal must drop below the
high setpoint, or above the low setpoint, by the hysteresis value before the channel leaves the alarm state
and the alarm is reset.