Fluid Components Intl ST51A - Appendix Bglossary; Abbreviations; Definitions

ST51A/ST75A/ST75AV Mass Flow Meters APPENDIX B – GLOSSARY
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APPENDIX B GLOSSARY
Abbreviations
Delta-R (ΔR)
Resistance differential
Delta-T (ΔT)
Temperature differential
DMM
Digital Multimeter
FCI
Fluid Components International
HTR
Heater
LCD
Liquid Crystal Display
LED
Light Emitting Diode
OIS
Ordering Information Sheet
RA
Repair Authorization
RTD
Resistance Temperature Detector
SFPS
Standard Feet Per Second
Definitions
Active RTD
The sensing element that is heated by the heater. The active RTD is cooled
due to increases in the process fluid flow rate or density (level sensing).
Control circuit
The portion of the level switch that conditions, converts, and scales the
sensing point (head) signal.
Level element
The portion of the level switch that contains the sensing points and process
connection.
Heater (HTR)
The part of the sensing element that heats the active RTD.
Local enclosure
The enclosure attached to the level element.
Reference RTD
The level element part that senses the fluid temperature.
Resistance differential
Delta-R (ΔR)
The difference in resistance between the active and reference RTDs.
Resistance Temperature
Detector (RTD)
A sensor whose resistance changes proportionally to detector temperature
changes.
Sensing element
The transducer portion of the instrument. The sensing element produces an
electrical signal that is related to the flow rate, density (level sensing), and
temperature of the process media.
Temperature differential
Delta-T (ΔT)
The difference in temperature between the active and reference RTDs.
Thermowell
The sensor element part that protects the heater and RTDs from the process
media.
Turndown ratio
The ratio of minimum flow rate to maximum flow rate.