20
(i.e.,
≤
5
μ
g/m
3
) for zeroing, as determined by another monitor (e.g., Thermo
Scientific DataRAM 4).
To zero the model
p
DR-1000AN by means of its Z-Pouch, proceed as follows:
•
Wipe the outside surfaces of the
p
DR-1000AN to remove as much dust from
those surfaces as possible before placing the instrument inside the Z-Pouch.
•
In a reasonably clean environment, open the zipper of the Z-Pouch and place the
p
DR-1000AN inside it. Close the zipper shut.
•
Open the small nipple on the Z-Pouch, and insert the fitting of the hand pump/in-
line filter unit into the nipple.
•
Start pumping the hand-pump until the Z-Pouch begins to bulge, and proceed
with the steps in Section 8.1, pressing the keys of the instrument through the wall
of the Z-Pouch. Then slowly continue to pump to maintain positive pressure
within the Z-Pouch.
•
After completing the zeroing (step 2. of Section 8.1) procedure, open the Z-
Pouch zipper and remove the
p
DR-1000AN. Close the zipper and flatten the Z-
Pouch while plugging its nipple, in order to prevent dust contamination of the
interior of the Z-Pouch.
•
The
p
DR-1000AN is now zeroed and ready for a measurement run.
6.5.2
Zeroing
the
model
pDR-1200
To provide the particle-free air required to zero the
p
DR-1200, either of two methods
can be used: a) place the instrument on a clean-air bench or in a clean room, or b)
connect to the cyclone inlet the green zeroing filter cartridge supplied with the
p
DR-
1200. In either case, proceed as follows:
•
After implementing either of the two methods, above, run the attached pump for
at least one minute (e.g., at 2 liters/minute), and then proceed as described in
Section 8.1 of this instruction manual, while continuing to run the pump (or
leaving the unit in the clean air environment).
•
Once the CALIBRATION: OK message appears on the
p
DR-1200 display, stop
the pump and disconnect the zeroing filter cartridge from the cyclone inlet (or
remove
p
DR-1200 from clean bench/room).
•
The
p
DR-1200 is now zeroed and ready for a measurement run.
Note: While the pDR-1200 is used to monitor high dust concentrations (
≥
0.5
mg/m
3
), the flow through its sensing chamber should not be stopped
before purging it, which can be done by connecting the green zeroing
filter to the cyclone inlet and continuing to run the pump for about 2
minutes before shutting it off. This is to prevent dust contamination of
the sensing chamber.
