IRIS S550, Applications Manual, Page: 6 / 19

increases the reliability of the S550 compared to
earlier approaches that used discrete analog
compo nents to implement four active filters. The
micro con troller also handles commu ni ca tions
with the P520/P522 signal processors.
WIRING OF VIEWING HEAD
Wiring of the viewing head is made to the
terminals on the rear backplane PC board (or
output module) on the P520 signal processor and
is made to the terminals on the lower right side of
the P522. These terminals are listed functionally
as follows:
TERM DE SCRIP TION
GND
Power Ground
+V +24 VDC power to view ing head
SC Shut ter Drive Sig nal to V.H.
SIG Flame Sig nal from V.H.
SIG GND Sig nal Ground
The figures on the previous pages show a four
conductor cable to the viewing head. Note that the
flame signal wire going to terminal SIG is
shielded and the shield is termi nated at both ends
of the cable(SIG GND).
The standard IRIS Model 500 cable is desig nated
as part number C328. It is specified as a four
conductor cable with one wire shielded. The
shield is used as the signal ground wire which
goes to terminal SIG GND on the P520/P522 and
to pin 3 on the viewing head plug. The shield is a
braided type for this appli cation (a foil type shield
should not be used) so that a solid signal ground is
maintained. This signal ground shield is also the
self- checking or shutter drive circuit return path. It
is recom mended that the IRIS cable be used for all
appli ca tions. Ref er to the diagrams on pages 3 and
4 for wiring details.
Connec tions of the IRIS cable to the viewing head
plug should be done as follows:
Remove the plug from its packaging and layout
the components.
1. Strip 2 inches of the cable outer cover from the
cable removing any cello phane wrap or filler
material and strip the insulation from the
shielded wire (if insulated over shield) a full 2
inches to expose shield.
2. Slide the shield back until a bulge develops
close to where the wire exits the cable outer
covering.
3. Carefully spread a few strands of the shield at
the bulge (making sure not to break any
strands) to cre ate an opening and slip wire out
of shield through opening.
4. Carefully return shield to original shape and
length by pulling gently, then cover with
plastic shrink tubing to prevent shorts.
5. Slide nut (with threads toward the cable end),
the washer and the grommet onto cable
approxi mately 6 inches.
6. Slip the cable through the bottom opening of
the connector making sure that the cable outer
jacket is secure under the cable clamp and
tighten the two screws on the cable clamp.
7. Reassemble the grommet, flat washer, and
cable entry nut and tighten.
8. Bef ore wiring to connector, strip each wire
3/8" as shown in assembly drawing on pre -
vious page.
9. Proceed to wire the connector as follows: (Ref -
er to drawings on page 3 for terminal
locations.)
Connect viewing head signal wire (the shielded
wire) WHT to terminal No. 1 by inserting into
opening and then tight ening the retaining screw.
Connect the self- checking signal wire BLK to
terminal No. 2. Connect the signal ground shield
from WHT wire with shrink tubing to terminal
No. 3. C 24 VDC power wire RED to
terminal No. 4. Connect the power ground wire
GRN to terminal No. 5. Assemble the back of the
plug and insert jackscrew through plug assembly.
PAGE 6
IRIS MODEL S550 APPLICATION MANUAL