Line C Control Point Instrumentation Flashcards
For control point instrumentation, what does RTD stand for?
Resistance temperature detector
What type of RTD is mostly used in the industrial sector?
Coiled element RTD
The known electrical resistance at a specific temperature of the metal that makes up an RTD allows the RTD to be accurate within its temperature limits.
True
What metal is most commonly used in an RTD in industrial applications?
Platinum
How does an RTD work?
The resistance increases as the temperature of the sensor increases
Which is the most common RTD wiring configuration that gives a good combination of accuracy and convenience?
3-wire
A 4-wire RTD gives the best accuracy even though most industrial controllers/measurement devices cannot make a true four wire measurement.
True
What is the characteristic of a 3-wire RTD configuration?
It allows the measurement to factor out the resistance of the leads
What type of circuit is used in an RTD to measure the resistance?
Wheatstone bridge
How does a thermocouple interpret changes in temperature?
Change in Voltage
A ____________ has wider operation ranges than an RTD.
Thermocouples
RTDs are more sensitive than thermocouples thus they react faster.
False
Which statement is true when comparing thermocouples to RTDs?
Thermocouples react faster than RTDs, but RTDs are more accurate
What can limit the maximum range of a thermocouple?
Its diameter
How does a pressure transducer work?
It converts pressure into an electrical signal
What produces the electrical signal in a pressure transducer?
Strain gauge
What types of electrical output is available for a pressure transducer?
Millivolt, 0-10 Voltage, 4-20 mA
How many platinum RTDs does a thermal mass flow meter use?
2
In a thermal mass flow meter, what task does each RTD perform?
One RTD measures the fluid temperature and the second maintains a constant temperature differential above the process fluid
What three things is an automatic O2 trim system designed to compensate for?
Fuel characteristics, temperature, barometric pressure
What sensor is the critical component used to reduce emissions in a modern biomass boiler?
O2 sensor
To give better control and more consistent/accurate positioning for a modulating burner, in what system are servo motors used?
In a parallel positioning system
