Honeywell SMV 3000 user manual Fault Detect Background

6.8 TempConf Configuration - PV3, Continued

T/C Fault Detect

Background

Select whether to turn on the function for T/C or RTD fault detection.

•	ON	– Any RTD or T/C lead breakage initiates a critical
		status flag.
•	OFFd	– Break in RTD sensing lead or any T/C lead initiates

a critical status flag.

d Factory setting.

You can turn the transmitter’s temperature sensor fault detection function ON or OFF through configuration.

•With the detection ON, the transmitter drives the PV3 output to failsafe in the event of an open RTD or T/C lead condition. The direction of the failsafe indication (upscale or downscale) is determined by the failsafe jumper on the PWA, (See Subsection 8.3).

•When fault detection is set to OFF, these same failsafe conditions result in the transmitter for an open RTD sensing lead or any T/C lead. But when an open RTD compensation lead is detected, the transmitter automatically reconfigures itself to operate without the compensation lead. This means that a 4-wire RTD would be reconfigured as 3-wire RTD, if possible and thus avoiding a critical status condition in the transmitter when the transmitter is still capable of delivering a reasonably accurate temperature output.

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