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DPM-RT-2 Operating Manual
7
Calibration Check
7.1
Using the Calibration-Check Plug
The analyser has been factory calibrated to deliver a linear output directly
proportional to the concentration of PM. Given the linearity of response, a simple
“Zero and Span” check provides an excellent and rapid confirmation of calibration
status. The supplied calibration-check tool generates the span response. The
procedure follows:
(a)
Put the instrument in “Continuous Measuring”
mode (
See Section 4.8 Continuous Measurement
),
with the sample probe resting in relatively clean air (i.e. not downstream of any vehicle exhaust).
(b)
Remove the Operating Plug from the rear panel of the analyser by rotating it counter-clockwise and
then pulling directly from its socket. If the plug has not been removed for some time, it may require
a firm pull to overcome O-ring friction. Occasional light application of silicon grease will help to
avoid this.
Calibration-Check Plug (left)
Operating Plug (right)
(c)
After carefully cleaning the calibration plug using a lint-free cloth (
DO NOT use paper tissue
), insert
the Calibration-Check Plug and rotate clockwise until it is firmly engaged on the stop pins. Ensure
that the plug is oriented so that black indicator / mark on the back face of the Calibration-Check
Plug is aligned with the black indicator / mark on the instrument case.
Back Face of Calibration-Check Plug.
Note: Serial # shown on Calibration-Check Plug is unique
to each instrument
(d)
Confirm that the numerical reading on the screen is approximately the same (±5%) as the number
labelled on the Calibration-Check Plug. It will take at least 5 minutes for the calibration plug to
warm up and arrive at its value.
(e)
If the displayed reading is still not ±5% of the number labelled on the Calibration-Check Plug
supplied with the instrument (number on Calibration-Check Plug is unique to each instrument),
some further adjustment will be required using specialist calibration equipment. In this instance,
the DPM-RT-2 instrument will need to be returned to your local service centre for further analysis.
*Importantly, the calibration-check plug should be returned with the DPM-RT-2 with each
recalibration as the numerical reading on the calibration-check plug changes after each calibration.
Chapter
7
