IGD 2-Wire Systems, Installer'S Manual

Page: 34 / 52

33
Pellistor (Catalytic) Flammable Gas Detector Interface
P
Y
W
The Detector Node PCB is equipped with a Pellistor or Catalytic flammable gas detector
interface. This supports all IGD manufactured pellistors as indicated below. Note that the
correct pellistor option must be selected in the setup software routine for the pellistor to operate
correctly.
The Pellistor can be mounted remotely from the PCB. When doing so do not exceed the
indicated cable length.
For remote mounting use 1.5mmSQ Cable. Do not exceed 10M
V DC
Volts
Com
2.20
IGD Pellistors Supported
Type Head Head
Current Volts
MK3 ATEX EXD IIC T6 360mA 2.2V
MK6 Safe Area 170mA 2.5V
MK7 Safe Area 170mA 2.5V
In operation and with zero air applied correctly to the detector the ‘balance’ between the two detector
‘beads’ as measured P-Y and Y-W should not show a difference of more than 70mV. If the difference
is larger than this then it could be an indication of aging or damage and the detector should be
replaced.
Note: The Pellistor ‘Type’ is selected using IGD service tool app or by using the setup routine in the
TOC-750 Software. Once selected this automatically sets the head supply voltage.
This will not normally be required if
other items of heavy electrical
equipment are not present
This cable to the pellistor may need
to be screened in electrically noisy
environments.