Fisher 244EH, 244ER manual Implementation, Transmitter Behavior with Intermittent Sensor Detect ON

Implementation

Figure 3-4. Open Sensor Response (Three Cases)

Transmitter Behavior with Intermittent Sensor Detect ON

When the Intermittent Sensor Detect feature is switched ON, the transmitter can eliminate the output pulse caused by intermittent open sensor conditions. Process temperature changes (ΔT) within 2% of the output range will be tracked normally by the transmitter’s output. A ΔT greater than 2% of the output range will activate the intermittent sensor algorithm. True open sensor conditions will cause the transmitter to go into alarm.

Transmitter Behavior with Intermittent Sensor Detect OFF

When the Intermittent Sensor Detect feature is switched OFF, the transmitter tracks all process temperature changes, even if they are the consequence of an intermittent sensor. The output delay due to the intermittent sensor algorithm will be eliminated.

The Intermittent Sensor Detect feature can be turned ON or OFF using a Model 244E transmitter with software version 5.4.1 or earlier with the Model 244EC software configuration tool when the transmitter is connected to the Model 244EC Configurator.

Turning the Intermittent Sensor Detect feature OFF does not affect the time needed for the transmitter to output the correct alarm signal after detecting a true open sensor condition. However, the transmitter may briefly output a false temperature reading for less than 0.5 seconds in either direction (see Figure 3-4)up to100% of output range.

(mA)	25
	20							High Alarm
Output
	15				Normal open sensor responses
Transmitter
	10					A false temperature output in
						either direction up to the
						threshold value (100 % of output
	5					range if Intermittent Sensor Detect
						is OFF) is possible when an open
						sensor condition is detected.						03
	0
												644
	0	0.2	0.4	0.6		0.8	1.0		1.2	1.4	1.6
					Time (seconds)							644-

Unless rapid response rate is necessary, the suggested setting of the Intermittent Sensor Detect mechanism is ON.

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