IRIS S55XX SERIES VIEWING HEADS APPLICATION MANUAL
PAGE 5
The diagram in Figure 1 shows the wiring of the view-
ing head connector to the signal processor using the
recommended IRIS type C328 cable. This cable has a
UL ITC rating and can be used in the US in hazardous
locations. Note that the flame signal wire is shielded,
and that the shield is terminated at both ends.
The shield is used as the signal ground wire which
goes to terminal SIG GND on the signal processor,
and to pin 3 on the viewing head plug. The shield
must be a braided type for this application in order to
maintain an electrical path. For this reason, a foil type
shield should not be used. This signal ground shield
is also the self-checking or shutter drive circuit return
path. It is recommended that the IRIS C328 cable be
used for all applications.
Connection of the IRIS type C328 cable to the view-
ing head plug is shown on the following page in
FIG-
URE 2, CONNECTOR WIRING
, and should be
done as follows:
Remove the cable entry nut from the plug housing.
Remove the rubber grommet and flat sealing washer.
With a pair of long-nosed pliers remove the center
ring only of the rubber grommet.
1. Strip 2 inches of the cable outer cover from the
cable removing any cellophane wrap or filler
material. Strip the insulation from the shielded
wire (if insulated over shield) a full 2 inches to
expose the 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 create an opening and pull the wire out of
shield through opening.
4. Carefully return shield to original shape and
length by pulling gently, then cover the shield
with heat shrink tubing to insulate it.
5. Slide the nut (with threads toward the cable end),
the washer and the grommet approximately six
inches onto the cable.
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. Strip each wire 3/8” as shown in the assembly
drawing figure 2 on the following page.
9. Proceed to wire the connector as follows: (Refer
to the wiring diagram figure 1 for terminal loca-
tions.)
Connect the viewing head signal wire (the shield-
ed wire) WHT to terminal No. 1 by inserting
into opening and then tightening 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.
Connect the + 24VDC power wire RED to termi-
nal No. 4.
Connect the power ground wire GRN to terminal
No. 5.
Assemble the back of the plug and insert the
jackscrew through plug assembly.
The cable at the signal processor end should be prepared
in a similar way to the plug end, particularly the shield
from the WHT wire. Follow the wiring connections as
shown in the wiring diagram figure 1, making sure that
the shield does not touch the other adjacent terminals.
VIEWING HEAD INSTALLATION
Before beginning the actual installation, determine
the best location for mounting the viewing head based
upon the following factors:
PRESSURE:
The viewing head lens will with-
stand 5 psi. If the lens assembly is exposed to
greater than 5 psi through the sight pipe, then
an isolation unit must be used. An IRIS isola-
tion unit with purge air entrance model ISO/
Unit is available as an accessory.
TEMPERATURE:
The viewing head will with-
stand an ambient temperature to 80° C (176°
F). However,
the case temperature of the
housing must not exceed 60° C (140° F)
.