Biosystems MultiPro Reference Manual - →
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4.2 and perform the fresh air calibration
adjustment then proceed to step 4.
4. Attach the calibration adapter and
connect the calibration cylinder to the
MultiPro as shown in figure 4.1. Flow
gas to the sensors.
5. Wait for the readings to stabilize. (Forty-
five seconds to one minute is usually
sufficient.)
Figure 4.1 Bump Test / Span Calibration
set up
6. Note the readings. Toxic and LEL sensor
readings are considered accurate in a
bump test if they are between 90%* and
120% of the expected reading as given
on the calibration cylinder. If the
readings are considered accurate, then
the instrument may be used without
further adjustment. If toxic and LEL the
readings do not fall within 90%* and
120% of the expected reading as given
on the calibration cylinder, then readings
are considered inaccurate. If readings
are considered inaccurate, proceed to
section 4.3 and perform the span
calibration.
*
The Canadian
Standards Association (CSA) requires the
instrument to undergo calibration when
the displayed value during a bump test
fails to fall between 100% and 120% of the
expected value for the gas.
Biosystems multi-calibration gas mixtures
contain approximately 18% oxygen.
During the bump test the oxygen sensor
should read within +/-0.5% of the level
given on the calibration cylinder.
4.2
Fresh Air/Zero Calibration
Fresh air/zero
calibrations may only be performed in an
atmosphere that is known to contain
20.9% oxygen, 0.0% LEL and 0 PPM toxic
gas.
To initiate the fresh air/zero calibration:
1. Press the MODE button three times
within two seconds to begin the fresh
air/zero calibration sequence. The
MultiPro will briefly display AUTO CAL
and then begin a 5-second countdown.
→
2. Press the MODE button before the end of
the 5-second countdown to begin the
fresh air/zero calibration. The fresh
air/zero calibration is initiated when the
MultiPro alternates between the following
two screens:
↔
3. The fresh air/zero calibration is complete
when the instrument begins another 5-
second countdown for the span
calibration. If span calibration is not
required, allow the countdown to reach 0
without pressing the MODE button.
4.2.1 Fresh air/zero calibration failure
In the event of a fresh
air/zero calibration failure,
the alarms will be
activated and the
instrument will display the
following screen. Note
that the sensor(s) that fail
the zero calibration are
shown (in this case, CO)
After 3 seconds, the
MultiPro will return to the
current gas readings
screen and the visual and
audible alarms will cease.
When fresh air/zero calibration is due, the
MultiPro’s display will show the warning
symbol while intermittently displaying the 0-
CAL icon in the gas readings screen until a
successful fresh air calibration is performed.
If a specific sensor has failed the fresh
air/zero calibration, it will be displayed with
the 0-Cal icon.
If a successful fresh air / zero calibration is
not performed prior to instrument shut down,
the MultiPro will note that Fresh Air
Calibration is due during instrument start up.