IRIS S550, Applications Manual, Page: 10 / 19

tolerences, so any other S550 will work virtually
the same as the one it replaces.
NOTE: the S550 is designed to work only with
newer P520/P522 signal processors. How ever,
besides working with newer signal processors,
S552’s and S556’s are designed to work also with
older P520/P522 and M502 signal processors;
with these they will operate at their default gain
settings.
AS SIGN ING DIF FER ENT S550 SET TINGS
TO CHAN NEL A AND B
With the P520/P522 an operator may assign one
group of S550 settings to Channel A and another
group of S550 settings to Channel B, just as he
would assign different Flame ON and Flame OFF
set points to Channels A and B. How one may
store settings for each channel in the P520/P522
will be briefly reviewed.
If the CHAN SEL input to the P520/P522 is open
or de-energized, then the Channel A lighted push-
button on the front panel will be continu ously ON.
If a voltage of 7.5V to 30V is applied across the
two CHAN SEL inputs, then Channel B will be
selected and the Channel B lighted push button
will be continu ously ON. When Channel A is
selected, any P520/P522 parameters changed (this
includes Flame ON and Flame OFF set points and
the analog gain of the P520/P522 as well as the
gain and filter selection for the S550) will be
stored for use when Channel A is selected.
Similarly, when Channel B is selected any
P520/P522 changes are stored for use when
Channel B is selected. When the CHAN SEL
input is changed, the P520/P522 changes the set
points in use accord ingly and sends the appro -
priate gain and filter selec tions to the S550
viewing head.
In the P520/P522 there is a way to observe and
change settings for the channel which is not
selected: simply press the other channel push
button - it will blink indicating that the selection is
temporary - and then proceed as if the CHAN SEL
input had changed. This method is available for
examining or changing Flame ON and Flame OFF
set points and other settings in the P520/P522. The
same pro ce dure applies to manually changing
S550 settings when the desired channel is not
selected: press the push- button for the desired
channel and then proceed. During the process of
examining or changing the S550 settings, with the
Channel A and B (NO and YES) push buttons, the
red LED for the channel which the changes apply,
will be blinking.
One should visually check which channel push
button is lighted when the S550 settings are being
reviewed or changed. It is easy to get into the S550
CAL modes with the wrong channel selected. For
example, if the Channel A LED is on or blinking
and one intends to press both buttons at the same
time to enter the CAL mode for Channel A, but,
instead, one presses the Channel B push button
well bef ore the Channel A push button, the
P520/P522 will think that the operator has
selected Channel B then subse quently pressed
both push buttons. Then, in the CAL modes, the
red LED for Channel B will be blinking, which is
not what was intended. If this happens, one should
get out of the CAL mode, select the desired
channel, and press both push buttons again to
reenter the CAL mode, but this time pressing both
push buttons at approxi mately the same time.
USING TWO VIEWING HEADS PER
AMPLIFIER
Two viewing heads can easily be hooked up to the
same amplifier using the V.H. A and V.H. B
inputs. To permit this to work properly the P520
or P522 should be wired so that a 24VDC channel
select signal will be applied simul ta ne ously to the
coil of the VH select relay and to the channel
select input. Then, when the channel selection is
changed, the alternate set of data inputs from
viewing head B will be switched into the signal
processor by the VH select relay and the processor
will apply a different group of set points and gains
in response to the A/B Channel switch.
There is no restriction on how viewing heads may
be mixed between the two channels. One can
have an S550 on one channel and an S511 on
another, or an S552 on one channel and an S556
on another, or any combination. Of course, the
earlier 500 series viewing heads - Models S506,
S511 and S512 - are not adjustable remotely as the
S550 family of viewing heads are. The P520 or
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IRIS MODEL S550 APPLICATION MANUAL