The post Detectors Used in Level Measurement first appeared on the ISA Interchange blog site.
Today’s automation industry quiz question comes from the ISA Certified Control Systems Technician (CCST) program. Certified Control System 
Technicians calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables. Click this link for information about the CCST program. This question is from the Level I study guide, Domain 1, Calibration. Level I represents a professional who has a five-year total of education, training, and/or experience.
Hydrostatic head, weight, radioactive properties, density and sonic detectors are all used in what methods of level measurement?
A) point
B) pressure
C) inferential
D) direct
E) none of the above
Bonus Question: What Celsius temperature reading is within an oven temperature of 215°F to 220°F?
A) 100
B) 110
C) 329
D) 338
E) none of the above
Direct measurement of level would involve a sight glass, or markings on the side of a tank that indicate level or perhaps a mechanical apparatus such as a float. All the measurements or devices posed by the question can serve to calculate the level or do calculate the level using ancillary information about the contents of the vessel. We call this calculation method inferential.
The correct answer is C.
This oven temperature question may seem silly in these days of high-powered handheld calculators. During the pre-microprocessed days, Celsius was converted to Fahrenheit by multiplying Celsius by 1.8 and adding 32° to get Fahrenheit.
The correct answer is E. The conversion range is 101.667 to 104.444.
Source: ISA News
