User manual
Operation
MarathonSeriesFA/FR 31
Figure27:DeadbandExample
6.2.11AmbientBackgroundTemperatureCompensation(FAModels)
The FA modelis capableof improvingtheaccuracy of target temperature measurementsby 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 overrangewith 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 beused 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
thecompatibilityrequirementsof connectedequipment).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 HoldandValleyHoldhave to be setto300.0seconds to
recognize this Reset.The Reset
signalwillcausethepeakorvalleyreadingthat thesensorisholdingtochangeimmediately tothe
currenttargettemperature.
962°C
958°C
Setpoint: 960°C
Relay Changes State
Time
Normal State Alarm Alarm Normal State
Deadband
Object Temperature