October 2006, Vol. 18, No.10
Test Your Knowledge of Instrumentation
True or False Questions:
- An electronic pressure sensor cannot accurately determine a liquid level if foam is present.
- Magnetic flowmeters are well-suited for measuring slurry and thickened sludge flows.
- A device’s range is defined as the upper and lower limits that the device can measure, receive, transmit, or record.
- Flow measurement can be broken into two major divisions: open channel and sludge.
Multiple Choice Questions:
The gradual shift in an instrument’s output reading when there is no change in the actual value is defined as what?
D. Dead band.
How many points should be used to calibrate a pH meter?
Which type of device is best at measuring low flows?
A. Parshall flume.
B. Rectangular weir.
D. V-notch weir.
What is the best strategy for choosing the range of a replacement flowmeter?
A. Install a meter with the same range as the old one even though the plant’s flow has increased.
B. Install a meter with a range that will best match the predicted flow in 10 years to avoid having to upgrade later.
C. Install a meter with a range that exactly matches the typical flow patterns at the moment.
D. Install a meter with a range that can accommodate current maximum flows, as well as the expected increase of a few years.
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Questions were developed by Steve Spicer and reviewed by the Association of Boards of Certification (Ames, Iowa) Validation and Examination Committee.
Water Environment Federation (1984). Process Instrumentation and Control Systems; Manual of Practice No. OM-6. Alexandria, Va.: Water Environment Federation.