RKI Instruments HS-94 - Manual (Page 7)

Note
The 94 series automatically checks battery voltage during start-up; if the measurement
is below 2.1V, the instrument will not operate. During normal operation, when the
battery voltage drops to 2.0V, the battery sign will blink on the display, a continuous
alarm tone will sound, and the display will show a blinking battery.
WARNING
The instrument does not monitor the atmosphere during a dead battery alarm. When
the low battery indicator flashes on the display, take the instrument to a non-
hazardous location to change the batteries. (See Maintenance-Batteries.)
C. Peak (Minimum) Hold Function.
Press the Mode switch twice to enter this mode. During use,the instrument
automatically latches onto the maximum gas reading for the toxic gases (and
onto the lowest reading for the Oxygen version). This reading is displayed on the
readout, and can be reset once the actual gas condition has cleared by pressing
the MODE switch once. The PEAK HOLD function will activate itself for any
alarm condition, and can be reset once the gas condition is below the alarm level
(or above the alarm level for the Oxygen version). To clear the peak (or
minimum) readings, press the mode switch once after the gas condition has
cleared.
D. Toxic Gas (H
2
S and CO) Exposure.
Press the MODE switch three times to display the TWA value (time weighted
average dose for the last 8 hours of operation of the instrument).
Press the MODE switch four times to display the STEL value (time weighted
average dose for the last 20 minutes of operation of the instrument).
The instrument will return to normal operation itself after 20 seconds of
displaying these modes. To bypass the 20 second delay, press the MODE switch
to return to normal operation immediately.
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