IRIS S550, Applications Manual, Page: 12 / 19

settings, of course, may be made. The auto mat ic
calibration process is not sacred; it only finds gain
values. The user may change these, if he wishes,
to suit his needs. For example, one may wish to
increase the gain so the nominal displayed value is
1500 instead of 1200.
Note that the calibration pro ce dure sets the gain of
the sensor not being used to zero, but one can
adjust the gain of the unused sensor so the S550
responds to both sensors. The S550 sums the
sensor outputs.
CHECKING OR CHANGING UV GAIN
At the front panel of the P520/P522 press both A
and B push buttons simul ta ne ously. The current
numerical data on the 4 digit display will be
replaced with “CAL?” meaning, “Do you wish to
Calibrate?” If you press YES you will enter the
Calibration mode described in the pre vious
section. Press NO to enter the Adjust mode. The
display will show “AdJ?” meaning, “Do you wish
to make manual adjust ments?” If you do, press the
button near YES, which is the B push button. The
display will show “AuNN” where NN is the
current UV gain with the range 00 - 99. A gain of
00 turns off the sensor. To change the UV gain use
the up or down push buttons. If you then press
YES the new value will be stored; if you press NO
(Channel A push- button) the new value will be
ignored.
CHECKING OR CHANGING IR FILTER
You next have an oppor tunity to change the IR
filter. The display will show “ArFN” where N is
the current filter selected ranging from 1 to 8. Use
the up and down push- buttons to change the filter
if you wish. See
COMPARISON WITH OTHER
MODEL 500 SERIES VIEWING HEADS
for a listing
of the high-pass frequencies for these filters. Press
YES to accept a new filter value or NO to ignore
any changes you may have made.
It is recom mended that the #3 default filter (33Hz
cutoff) be used for all of the initial setup proce -
dures described in this manual. Further infor
-
mation on how these filters can affect the discrimi -
nation ratio is found in the
P520 APPLI CATION
MANUAL
and in the
P522 APPLI CATION MANUAL
in the section
MULTI BURNER REQUIRE MENTS.
For further infor mation please call the factory or
contact IRIS Systems Inc. See page 13 for contact
infor mation.
CHECKING OR CHANGING IR GAIN
You now have an oppor tunity to make a final
adjustment of the IR gain. After the filter
selection, the display will show “ANNN” where
NNN, the IR gain, ranges from 000 to 699. The up
and down push- buttons can be used to change the
IR gain. Changed values can be accepted by
pressing YES or ignored by pressing NO. If the
S550 settings are changed, the display will show
“----” indicating that the values are stored in
EEPROM bef ore continuing with the normal
numerical display.
If you do change the IR gain you may be surprised
to see the displayed gain values “jump” as you
scroll through them. As you increase the gain from
zero you will see this sequence:
000 - 099
150 - 199
250 - 299
350 - 399
450 - 499
550 - 599
650 - 699
The two least significant digits are linear gain
multi pliers; e.g., from 150 to 199 is a 99/50
increase in gain. But the most significant digit is
nonlinear; with each step change in the most
significant digit, the gain doubles. For example, a
setting of 250 has twice the gain as a setting of
150. Now it is possible to see why, as the gain is
increased from 150 to 199 the next step is to 250;
an increase from 150 to 199 is an increase of
99/50, which is a gain increase of almost 2, but the
next step to 250 is to a gain increase, theore ti cally,
to exactly 2. This relationship is true of all the
gains to 699.
The two least significant digits can be used below
050 down to 000; 000, of course, selects a gain of
zero (which turns OFF the sensor). When the
display is ramped down from 699 the following
sequence will be seen:
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IRIS MODEL S550 APPLICATION MANUAL