PR-805/810/810
L
User Manual
60
O
NE
T
IME
C
ALIBRATION
During a
One Time Calibration,
a photometer calibration factor is established by first making a
measurement and then using the user entered Source value to calculate the correction factor. The
correction factor is generated by:
��
𝑤
�������
=
𝑈
���
�������
𝐿
���������
���������
�
��������
Note: The One Time PMT Calibration option will only allow a correction of ±25% from the
ORIGINAL FACTORY CALIBRATION FACTOR. If the calculated correction factor is out of this
range a
“
Can't calibrate PMT
”
error will be displayed. Contact factory immediately if this
occurs.
To perform the calibration:
Step 1)
Align and focus the PR-8XX on the source to be measured. Make sure the source and
instrument are sufficiently warmed up.
Step 2)
Click on
Menu
→
Setup
—
PMT Calibration
.
FIGURE 63. PMT CALIBRATION SCREEN.
Step 3)
From the
PMT Calibration Screen
(see Figure 63), Click the
▲
or
▼
icons in the
One
Time Calibration
field so that it reads
Enabled.
Step 4)
Enter the absolute value of source being measured, by clicking on the
Luminance of
Source
field.
It is recommended that an Illuminant A source be used at this point.
Step 5)
Press the
Measure Button
to begin the calibration sequence.
Step 6)
Click
Yes
in the screen that displays
“
Do you want to begin the Calibration Sequence?
”
.
Step 7)
Following the measurement, the PMT (Photometer) factor is automatically calculated. At
this point, all successive photometer measurements, regardless of the aperture used, will
use this factor when displaying the measured luminance.
