IRIS S55XX SERIES VIEWING HEADS APPLICATION MANUAL
PAGE 11
adjustment for the selected sensor; the gain for the
sensor not selected is set to zero. The CAL feature
narrows the displayed count to about 1200, and au-
tomatically sets the Flame ON set point to 800 and
the Flame OFF set point to 600. The filter selection
remains unchanged.
Calibration Procedure:
1) Perform a preliminary sighting of the viewing
head, aiming for a high signal strength, as indi-
cated by the digital readout on the S550B. The
upper display will indicate the IR value in red, the
lower display indicates the UV value in green.
2) Ensure that the external input for CHAN SEL
is properly set for the channel about to be cali-
brated, and that the channel LED is illuminated.
When using the calibrate feature, the option of
working with the channel that is not selected by
the external input is not available.
3) Bring the firing rate of the burner to a low fire
condition.
4) If the flame relay has not yet energized, adjust
the flame on & off set points so that it does. If
“CAL” was activated without the flame relay be-
ing energized, the following display will show:
“bon?”. Press the reset button to return to the
previous state.
5) Determine whether to calibrate using the UV or
IR sensor. See the earlier sections on IR DETEC-
TOR and UV DETECTOR. At the front panel of
the P520 or P522 press both A and B push but-
tons simultaneously.
The display will respond with “CAL?”.
Press YES. The display will then show “CALu”.
Press YES to calibrate the UV response, else
press NO.
If NO is pressed, the display will show “CALr”.
Press YES to calibrate the IR response. (Pressing
NO will return the P520/P522 to normal opera-
tion, exiting the S550B CAL mode.)
The P520/P522 will automatically adjust the gain
for the selected sensor; this takes a few seconds. If
this adjustment is successful the display will show
“----”, and the P520/P522 will return to normal
operation, displaying a reading of 1100 to 1300.
However, if the signal input is too low, the P520/
P522 will display “2-Lo”. Press the RESET but-
ton to return to the previous settings. If the signal
level is too high, the display will show “OriF”.
(See the section on
ORIFICING
on page 9.)
Press RESET to return to the previous settings.
6) If step 5 was successful, re-aim the viewing head
for a final adjustment using the digital readout
to adjust the viewing angle for a maximum
signal strength. The CAL sequence should then
be repeated as in step 5). The Flame Relay will
remain energized. The display should show a
reading between 1100 and 1300.
7) Review the settings for F.F.R.T. And TIME DE-
LAY ON and adjust if necessary.
EXAMINING THE RESULTS OF GAIN SETTINGS
FROM CALIBRATION
The gain settings determined automatically by the cal-
ibration procedure described above, may be viewed
by following the procedure for checking or changing
the UV or IR gain described below. If needed, chang-
es can be made to these settings as required, to suit a
particular circumstance.
For example, the gain could be increased so that the
nominal displayed value is 1500 instead of 1200. Note
that the calibration procedure sets the gain of the sen-
sor not being used to zero, but the gain of the unused
sensor can be adjusted so that the S550B viewing
head responds to both sensors. Both sensor outputs
are summed.
CHECKING OR CHANGING UV GAIN
On the P520/P522 front panel, press both A
and B push buttons simultaneously.
The display will read: “CAL?” meaning, “Do
you wish to Calibrate?”
Pressing YES will enter the Calibration mode
described in the previous section. Press NO to
enter the Adjust mode. The display will show
“AdJ?” meaning, “Do you wish to make manu-
al adjustments?”. Press “YES”
The display will show “AuNN” where NN is