PR-680/680L User Manual
23
N
EUTRAL
D
ENSITY
(ND)
F
ILTER
(
OPTION
)
The PR-680/680L can be optionally equipped with a neutral density filter, ND1. This filter allows for
signal attenuation of 10 neutral density filters should be used when an Overload condition is reported by
the instrument.
•
Click on the
▼
or
▲
icon in the
ND
field to select the desired value. Choices are
Open
and
ND1.
S
ETTING THE
G
AIN
The PR-680/680L photometer mode utilizes four Gain settings, 1X, 10X, 100X and 1000X. These gains
are analog gains therefore by increasing the gain, the measurement noise increases proportionally. To
help average the noise, the
Frequency Response
value can be modified.
To select the gain:
•
Touch the
▼
or
▲
icon in the
Gain
field to select the desired value. Choices are
1X, 10X, 100X
and 1000X / Maximum (on PR-680L Only).
G
AIN
M
AXIMUM
(PR-680L)
The PR-680L is equipped with a highly sensitive PMT, and can measure 2 decades lower than the PR-680.
To achieve higher sensitivity a Gain of “Maximum” can be selected. When gain “Maximum”
is selected,
the PR-680L exposure time can take as long as 10 seconds (determined by Max. Time entry value).
When the PR-680L photometer is set into Adaptive mode the instrument can go into Maximum gain,
based on source level.
M
AX
.
T
IME
(PR-680L)
See information above. Max. Time range can be set anywhere between 200
–
10,000 msec.
S
ETTING THE
F
REQUENCY
R
ESPONSE
The
Frequency Response
(measurement bandwidth) is modified by inserting various IC networks before
the ADC. These filters act as high frequency rejection and help to electronically average the signal. The
available filter (bandwidth) values are:
OPEN (3 µsecs)
50 KHz (20 µsecs)
15 KHz (66.7 µsecs)
600 Hz (1.67 msecs)
200 Hz (5 msecs)
10 Hz (100 msecs)
1.
Touch the
▼
or
▲
icon in the
Frequency Response
field to select the desired value. Choices are
OPEN, 50 KHz, 15 KHz, 600 Hz, 200 Hz and 10 Hz.