RKI Instruments HS-94 - Manual (Page 8)

4 . Auto Zero/Span
To automatically adjust the zero point for H
2
S or CO, (or the span to 20.9% for
oxygen), take the instrument to a known fresh-air environment. With instrument in
normal operation, press and hold the AIR button. The unit will beep three times,
and then give a double beep indicating that it has adjusted to the surrounding
atmosphere.
5. Alarms
Gas Level Alarms
The 94 Series instruments have standard alarm points as listed below:
OX-94 19.5% decreasing, 23.5% increasing
CO-94 25 ppm increasing, 25 ppm TWA, 400 PPM STEL
HS-94 10 ppm increasing, 10 ppm TWA, 15 ppm STEL
When an alarm point is exceeded, the instrument sounds a pulsed tone, and the
display reading will blink. In the case of TWA or STEL alarms, the display will also
indicate which alarm level has been exceeded. The instrument reading will
automatically latch onto the highest reading (or lowest reading for low oxygen
levels). To reset, press the MODE switch once. If the gas concentration has dropped
to below the alarm point, the alarm will silence, and the unit will give the current
reading. If the unit has not dropped to below the alarm point when the MODE
switch is pressed, then the audible alarm will still sound and the unit will latch onto
the new reading present at the time the MODE switch was pressed.
Safety Self-Check
The 94 Series instruments continuously monitor themselves for proper operation. If
a malfunction occurs, a steady “trouble” tone will sound. There are two modes of
malfunction that will sound a steady
“TROUBLE” alarm. These are:
LOW BATTERY This alarm will sound if the batteries are too low
to operate the instrument. Replace the batteries
before further use.
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