Thermo EPD Mk2, Technical Handbook

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EPD/HB/40521/000
ISSUE 5
EPD TECHNICAL HANDBOOK Page 21
Figure 3.3 - Dose Rate Alarm Example
The four most significant digits of the alarm ‘Off’ and the alarm 'On' thresholds can be
viewed on the EPD LCD and, if user has authority to modify the thresholds, changed
using the function button (see Section 3.5.9).
3.2.4 Over-Range Indication
If a dose rate exceeds 1Sv/h, or if a dose store increments above 1.0Sv, an over-
range alarm will occur. The sounder (if enabled) will sound and the LED will flash (if
enabled). The over-range alarm will also cause the LCD display to flash every
second.
Notes :
1. The over-range alarm condition is latched and the LCD will continue to flash
even after a temporary dose-rate over-range condition has cleared. The over-
range conditions are recorded in the EPD EEPROM and must be cleared
over the IR communications link before the display will stop flashing.
2. The over-range alarm can be muted ( if enabled ). The EPD will not recur
after muting should over-range conditions re-occur (e.g. in the case of a
second dose-rate over-range alarm ), until the latched condition has been
cleared over the IR communications link. However the LCD will continue to
flash.
3. The ADS dose over-range alarm only operates if the unit is ADS issued.