Fluke Biomedical 942A-200L-M4 - Manual (Page 52)

942A-200L-M4 & 942A-200L-M5 UDR
Operator Manual
3-12
No Count Failure
If no pulses are received by the UDR for five minutes, a no count failure is detected. A no count alarm
usually indicates a failure in the detector or UDR detector high voltage supply. The UDR display,
however, may read zero for five minutes or more without a low signal fail alarm. The No Count failure
alarm can be disabled by removing jumper JP3-4 from the UDR main board.
Power Failure
If power is lost to the UDR, the bargraph, alarm indicators, and the display are blanked (turned off). The
HIGH, WARN, and FAIL relay coils de-energize.
MPU Failure (Watchdog Timer)
If the fail timer circuit, which checks the MPU (main processor) function, is allowed to time out (because of
a hardware failure), a failure condition will be indicated.
Anti-Jam Trip
Should the detector output exceed the UDR anti-jam circuit threshold, the anti-jam fuse opens and the fail
logic will illuminate the FAIL LED, and de-energize the Fail relay.
3.8 Configuration Functions
The UDR contains a series of eleven hardware jumpers and up to nine user specified set points that
affect operation of the unit.
The jumpers are designated as JP1 and JP2, JP3-1 through JP3-5, and JP4 through JP7. Refer to the
main circuit board assembly drawing located in Appendix B of this manual for jumper locations. The
functions affected by JP1 through JP7 are described in the following paragraphs and shown in Table 3-1.
Microprocessor Reset (JP1)
Jumper JP1 permits local reset of the microprocessor without cycling AC power.
PROM Type (JP2)
Jumper JP2 must be installed in position 2-3 for use with the 27256 PROM installed.
Count Time Selection (Statistical Accuracy JP3-1 and JP3-2)
The user can specify the statistical accuracy of the displayed radiation value with the use of JP3-1 & JP3-
2. This statistical accuracy selection affects count time and consequently, the update time of the display.
Refer to Table 3-1 for additional information.
Alarm Reset (Acknowledge JP3-3)
1. JP3-3 OUT - The unit resets alarm indicators and alarm relays after the radiation value falls below
the set point without regard to the alarm acknowledge pushbutton.
2. JP3-3 IN - The unit maintains the alarm indicators and alarm relays in the alarm state until the
alarm acknowledge pushbutton has been pressed and the radiation value falls below the set point.
If the alarm acknowledge pushbutton is pressed while the radiation value is still above the set point,
the flashing indicator will go to a steady state ON condition.
The UDR is normally shipped from the factory with JP3-3 in.