Operation
MarathonSeriesFA/FR 31
Figure27:DeadbandExample
6.2.11AmbientBackgroundTemperatureCompensation(FAModels)
The FA modelis capableof improving the accuracyof target temperaturemeasurements by taking
into account the ambient, or background, temperature. This feature is useful when the target
emissivity is below 1.0 and the background temperature is not significantly lower than the target
temperature. To utilize this feature, you must
enable the sensor with the background temperature
featureviatheDataTempSoftware.
6.3InputsandOutputs
6.3.1MilliampOutput
Themilliampoutput is an analogoutputyou can connect directly to a recordingdevice (e.g., chart
recorder), PLC, or controller. The analog output resolution for all models is 0.5°C or 1°F. The mA
output can be forced toa specificvalue, underrange, or overrange with a2‐ way RS485 command.
Thisfeatureisusefulfortestingorcalibratingconnectedequipment.
6.3.2RelayOutputs
Therelayoutputisusedasanalarmforfailsafeconditionsorasasetpointrelay,refertosection10.2
Fail‐Safe Operation, p. 46. Relay outputs relate to the currently displayed temperature on the LED
display. The relay output can be used to indicate an alarm state or to control external actions. The
relay can be set to either NO (Normally Open) or NC (Normally Closed) with a 2‐ way RS485
command(dependingon
thecompatibilityrequirementsofconnectedequipment).Therelaycanbe
forcedonoroffviathe2‐wayfortestingconnectedequipment.
6.3.3Trigger
Peak Hold and Valley Hold can be Reset by shorting the Trigger input (labeled TRIG) to Ground
(labeledGND)foraminimumof10msec.Thiscanbedoneeitherwithamomentaryswitchorarelay.
BothPeak Hold andValleyHoldhave tobe set to300.0secondsto
recognize this Reset.TheReset
signalwillcausethepeakorvalleyreadingthat thesensorisholdingtochangeimmediatelytothe
currenttargettemperature.
962°C
958°C
Setpoint: 960°C
Relay Changes State
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