Fluid Components International FLT93 Nuclear - Manual (Page 47)

FLT ® Series FlexSwitch TM APPENDIX B - GLOSSARY
Fluid Components International LLC 47
APPENDIX B GLOSSARY
Abbreviations
Delta-R (DR) Differential Resistance
Delta-T (DT) Differential Temperature
DMM Digital Multimeter
DPDT Double Pole Double Throw
FCI Fluid Components Intl
HTR Heater
LED Light Emitting Diode
POT Potentiometer
RA Return Authorization
RTD Resistance Temperature Detector
SFPS Standard Feet Per Second
SPDT Single Pole Double Throw
Defi nitions
Active RTD The sensing element that is heated by the heater. The active RTD is cooled due to increases in the
process fl uid fl ow rate or density (level sensing).
Differential resistance
Delta-R (DR)
The difference in resistance between the active and reference RTDs.
Differential temperature
Delta-T (DT)
The difference in temperature between the active and reference RTDs.
Heater (HTR) The part of the sensing element that heats the active RTD.
Local enclosure The enclosure attached to the sensing element. (Usually contains the control circuit and mounting socket.)
Reference RTD The part of the sensing element that senses the process media temperature.
Remote enclosure An optional protective enclosure for the control circuit. Used when the control circuit must be located away
from the sensing element.
Resistance Temperature
Detector (RTD)
A sensor whose resistance changes proportionally to temperature changes.
Sensing element The transducer portion of the instrument. The sensing element produces an electrical signal that is related to
the fl ow rate, density (level sensing), and temperature of the process media.
Thermowell The part of the sensing element that protects the heater and RTDs from the process fl uid.
Turndown The ratio of the upper to lower fl ow rate values.