IRIS MODEL 700/800 APPLICATION MANUAL
PAGE 7
custom cable lengths up to 4000 ft. may be ordered. This
custom cable C-330 may also be purchased from IRIS.
The customer may also supply his own cable; IRIS will
supply the mating viewing head connector along with
the LED indicator assembly which goes inside the
connector
. The use of shielded cable is recommended,
either an overall shield or a cable with a shield for the
signal line. The shield should be connected to GND at
the processor end and to the ground wire at the viewing
head end. The cable diameter should not exceed .307"
in order for it to go through the hex bushing in the
connector. But note that wiring the cable to the
connector is not easy because of the limited space.
Also, the LED indicator assembly must be mounted
inside the connector and, preferably, soldered in place.
NOTE: FOR CLASS I, DIV 2 RATING,
CABLING
IN HAZARDOUS LOCATIONS
MUST COMPLY WITH NEC ARTICLE 500
REQUIREMENTS.
In particular, in the US, cables should have UL’s ITC
rating; in Canada, cables should have CSA’s CIC rating.
The recommended C-330 cable has both ratings.
Note: To obtain a NEMA 4X seal between the
connector and the viewing head, tighten the metal
connector ring securely using a pair of pliers.
PROTECTING THE VIEWING HEAD CABLE
It is usually desirable to mechanically protect the cable
going to the viewing head. Flexible conduit and adapt-
ers can be supplied for this purpose. See Figure 12.
The 700 L
TA (Liquatite Adapter) is a custom part sup-
plied by IRIS; it screws into the right-angle connector
in place of the standard hex bushing. Con74 is a Tho-
mas and Betts TAB5330 Liquatite Fitting which is de-
signed to give a watertight seal for Cdt02 Flexible
Liquatite Conduit, part number LT-516 by Electra-Flex.
These components have internal dimensions to clear a
5/16" diameter cable. For each viewing head a 700 LTA,
a Cdt02 flexible conduit, and two Con74s will be needed.
IRIS will supply the 700 LTA. IRIS can also supply the
Cdt02 and Con74s, or these parts can be purchased
commercially. The customer can fit the Liquatite flex-
ible conduit over the cable supplied with the viewing
head by first unscrewing the hex bushing from the con-
nector and removing it from the cable and then sliding
the 700 LTA, Con74 and Cdt02 assembly over the cable
and screwing the assembly into the right-angle con-
nector. The Cdt02 flexible conduit is terminated with
the second Con74 Liquatite fitting which ends with a 3/8"
NPT thread. Note that when the wiring needs to meet
Class I, Division 2 requirements for use in hazardous
locations and when conduit is used, the conduit must be
sealed where the cable passes from the hazardous lo-
cation to the non-hazardous location in order to keep
potentially hazardous gases from being conducted into
the non-hazardous area.
GREEN AND ORANGE LED INDICATIONS
The connector has orange and green LEDs which can
be viewed from the rear of the connector. The green
LED displays the pulses out of the viewing head and
an orange LED shows that the self-checking signal from
the signal processor is reaching the viewing head. If
power is on at the signal processor, the orange LED
should flash at one pulse per second, even if the viewing
head is not plugged in. This is helpful in trouble-shooting.
With no flame signal present, the green LED will flash
one pulse per second in step with the self-checking
signal. The viewing head is sending back an ID pulse;
this is part of the self-checking system. When a flame
is present, the green LED will blink at a rate proportional
to the flame signal, except that the pulses are interrupted
once per second when the self-check pulse arrives at the
viewing head. The pulse rate of the green LED flashes
can be used for aiming the viewing head.
VIEWING HEAD MOUNTING BLOCK
The viewing head is held firmly in place in its mounting block
by two galvanized steel latches. The mounting block is made
from a hard Delrin rated for continuous service to 82°C
(180°F). An alternative mounting block made from Ultem
1000 is available, rated for continuous service up to 160°C
(320°F).
Both mounting blocks have a 1/4-18 NPT female thread
for a purge air connection. While it is true that the
viewing head is rated for operation to 85°C (185°F),
this temperature is still much lower than the tempera-
ture in a boiler or furnace, so continuous purge air must
be provided.
SETTING THE VIEWING HEAD GAIN
The gain of the new intelligent IR and UV viewing heads
can be adjusted. At power-up, Model 700 signal proces-
sors display codes to tell the operator what type of view-
ing head and what gain is being used. Typical displays
are “r7” for the IR VH, “u3” for the UV VH and “U5”
for an older UV viewing head. The numeric digit indi-
cates gain. For the intelligent UV and IR viewing heads,
the gain can be adjusted from 1 to 9 with a gain of 5
being the factory default gain. To change the gain, press
To Next Page
Loading...
Need help?
General
