Level Flashcards
What does the timing circuit in a magnetostrictive level TX to determine the process level?
Use the speed of a torsional (mechanical) wave along a wire to find the float and report its position.
List three operating principles on which the operation of the optical level instruments can be based.
- Reflection
- Refraction
- Transmission
At which point are the two probes on the thermal probes close to the same temp?
When they are submerged.
What is the problem with cage mounting level transmitters?
Temp diff between cage and vessel will leave a level difference.
List three ways to calibrate a capacitance level TX
- Wet
- Dry
- Factory
3 styles of capacitance probes
- Sheathed
- Coated
- Bare
List 2 most common styles of ultrasonic point level management.
- Damped Vibe
- Absorbtion
What is the term when an ultrasonic meter stops working when the level gets too close to the TX
Ringing
What is the advantage of using a temp input with an ultrasonic level TX
Helps change in density
What are two special features that are commonly available with microprocessor-based ultrasonic level transmitters?
- Volume calculation
- Detecting false echo’s
What is the difference between ultrasonic and radar?
Ultrasonic: uses sound waves
Radar: uses radio waves.
What is the minimum dielectric of solids or liquids for ultrasonic to to work?
1.4
What is the primary sensing element used to detect vessel weight.
Load cells
What is the primary sensing element used to detect vessel weight?
Load cells
Does a change in density effect the measurement accuracy?
Yes
