Calibration
H25-IR
26
Instruction 3015-5286
3.4.2 Improving PPM Measurement Accuracy using the CAL Factor
The CAL Factor can be adjusted to improve the accuracy of the ppm measurement by calibrating the
instrument on the gas being measured. The accuracy of the ppm measurement after performing this procedure
will equal the accuracy of the gas sample, ±1%. Note that the accuracy of the instrument’s ppm measurement
depends on the accuracy of the gas sample.
The new CAL Factor is determined by sampling a known dilution of gas whose accuracy is better than the ppm
measurement accuracy as stated in Section
6 Troubleshooting
. The concentration of the sample must also be
corrected for ambient temperature and pressure at the time of calibration. A minimum sample size of 5 liters is
required.
Calibration is best performed at or near full scale. It can, however, be done at any concentration and ideally in
the range where maximum accuracy is desired down to, but not below, 100 ppm.
The instrument should be operating for at least 30 minutes prior to performing a calibration.
Verify that the current CAL Factor is set to 1.000 by selecting the Main Menu > CAL DATA > CAL FACTOR
function. If necessary, reset the CAL Factor to 1.000. Refer to Section
3.4.3 Adjusting the CAL Factor
.
With the instrument operating in its ppm measurement mode (refer to Section
4.2.8 Measuring the PPM Level
),
insert the probe tip into the gas-sample bag and allow the instrument to sample until the ppm reading on the
display is stable. At this time record the ppm reading. The new CAL Factor is computed by dividing the known
gas concentration value by the measured value. Typically this number will be between 0.95 and 1.05. Enter the
new CAL Factor as described in Section
3.4.3 Adjusting the CAL Factor
.
IMPORTANT!
If the instrument is switched back to measuring the leak-rate, then the instrument must be
recalibrated on the gas being measured.
3.4.3 Adjusting the CAL Factor
Display the Calibration Data menu by first pressing
both
the
ENT
and
ESC
buttons on either the instrument’s
front panel or Smart probe at the same time to display the Main menu. Next, use the
Up
and
Down
buttons to
highlight “CAL DATA”, and then press
ENT
to display the Calibration Data menu.
Main Menu:
SYSTEM
LOG
SETUPS
CAL
DATA
DIAGNOSTICS
From the Calibration Data menu, highlight “CAL FACTOR” and press
ENT
to display its setup screen. Use the
Left
and
Right
buttons to move the blinking cursor across the screen to highlight the digit to be modified, and
then use the
Up
and
Down
buttons to modify that digit. Press
ENT
to save the new CAL factor value and return
to the Calibration Data menu.
CAL FACTOR
1
.000
FOR R134A
K1=310.89 K2=703.7 K3=1460.3
K4=0.0 K5=0.0
Calibration Data Menu:
CAL TYPE
EXT
RATE
EXT
GAS
TYPE
CAL FACTOR
RESTORE
FACTORY
CAL
CAL
INTERVAL
ENFORCE CAL INTERVAL
LAST CAL DATE
Summary of Contents for H25-IR
Page 6: ...Contents H25 IR iv Instruction 3015 5286 Notes ...
Page 26: ...Preparing for Operation H25 IR 20 Instruction 3015 5286 Notes ...
Page 34: ...Calibration H25 IR 28 Instruction 3015 5286 Notes ...
Page 43: ...H25 IR Operation Instruction 3015 5286 37 Notes ...
Page 68: ...Specifications H25 IR 62 Instruction 3015 5286 Notes ...
