Fluke Biomedical 942A-200L-M4 - Manual (Page 50)

942A-200L-M4 & 942A-200L-M5 UDR
Operator Manual
3-10
- RATE alarm LED returns to normal
- CHECK SOURCE LED turns off
- Analog Outputs return to normal
The Trip Test function is exited by pressing the Acknowledge push button.
When the ACK push button is pressed and released:
- Bar graph returns to normal
- HIGH alarm LED stops flashing
- HIGH alarm returns to normal
- WARN alarm LED stops flashing
- WARN alarm returns to normal
3.7 Alarms
The alarm functions provided by the UDR include HIGH, WARN, FAIL, UNDERRANGE and
OVERRANGE. The HIGH, WARN, and FAIL alarms drive relay contact outputs. Some operating modes
of the UDR disable alarms. The user is cautioned to read and fully understand Section 3.
Alarm Logic Types
Alarm logic defines whether the alarm is reset manually or automatically and whether alarm relay coils are
energized or de-energized in normal operation.
Standard alarm reset logic for the UDR is manual reset for the HIGH, WARN, and OVERRANGE alarms,
and auto reset for the FAIL and UNDERRANGE alarm. Failsafe operation is also standard.
Manual Reset
When an alarm trips, the relay coil goes to its abnormal position. For the HIGH and WARN alarms, the
indicator flashes until the alarm is acknowledged by pressing the ALARM ACK button on the UDR. The
indicator then remains steady on until the alarm condition becomes false. At that time, the alarm resets by
turning the indicator off and returning the contact to its normal energized position.
Auto Reset
When an alarm trips, the contact goes to its abnormal position. The indicator goes steady on. When the
alarm condition becomes false, the alarm automatically resets, returns the relay coil to normal position,
and turns the indicator off.
Auto reset may be selected for the HIGH and WARN alarms by removing jumper JP3-3 from the UDR
main board.
Standard relay operation for the UDR is fail-safe. When the unit is powered, the relay coil energizes. If
power is lost to the relay coil, or an alarm condition occurs, the relay de-energizes, giving a trip indication.
This logic provides fail-safe operation for the alarm function.
HIGH Alarm
The HIGH alarm condition is “true” when the display CPM rate is greater than or equal to the HIGH alarm
set point and “false” for all other conditions.
The standard logic for the HIGH alarm is fail-safe, manual reset.
When the HIGH alarm is tripped, the red HIGH alarm indicator begins flashing, the bargraph goes to red,
the HIGH alarm relay coil de-energizes, and the UDR sets its auxiliary output high. When the alarm is
acknowledged, the HIGH alarm indicator goes steady on and the UDR sets its auxiliary output low. The
auxiliary output on the UDR can be used to drive a remote alarm/alarm indicator.