Special Considerations When Using Catalytic Sensors - Honeywell Touchpoint Pro Technical Handbook

14.7.3 Action on Falling Alarms
Full Scale Exceeded and Over Range Warning may be set on channels using falling gas alarms, for instance oxygen. The
warning acts on the configured full scale value.
For instance, if the full scale of an oxygen channel is set to 25% Vol, with Full Scale Exceeded set to 100% FSD and Over
Range Warning set to 110% FSD then:
Full Scale Exceeded Warning
Over Range Warning
If no rising alarm is set on the channel, but the gas reading rises above the configured levels, a Full Scale Exceeded or
Overrange Warning may be unexpectedly displayed with no corresponding alarm. This indicates a high concentration of gas
not a low concentration.

14.8 Special Considerations when using Catalytic Sensors

Touchpoint Pro continually carries out diagnostics to prove that the system is operating correctly and faults such as wiring
faults will clear automatically when the system detects that the fault has been corrected.
In rare circumstances (due to insufficient oxygen for the sensor to operate correctly) a high gas concentration could occur
while the system is in fault, and which may not be detected by the system due to the fault. It is therefore highly
recommended to configure at least one Relay Output to latch on fault on channels that are used with catalytic sensors.
14.8.1 Configuration of Relay Outputs
Each output must be configured as Normally Energized, Alarm Update Enable not selected, and Latch Function selected, as
shown in the following example:
Auxiliary Output Enable should normally be selected if any load is connected to the module auxiliary output supplies (e.g. a
sounder or a beacon). A fault will then be generated if the output current limit is exceeded.
Each output must be configured as Output Type Normal, with a cause and effect matrix similar to the following example.
The cause and effect matrix must include all channels using catalytic sensors, in this instance three mV channels.
ID/Location
Select All
mV Channel 1
mV Channel 2
Part. No. 2400M2501_6
NORMAL OPERATION
will be displayed when the gas reading exceeds 25% Vol
will be displayed when the gas reading exceeds 27.5% Vol
Table 43. Action on Falling Alarms
Figure 92. Fault Latch Output Configuration
AL1 AL2 AL3 FLT INH
122
WRN
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