ISA Certified Control Systems Technician (CCST) program

CCST

Certified Control System Technicians (CCSTs) calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables.

CCST question

Which of the following calibration instruments will be the best choice to calibrate a high-range electronic pressure transmitter for a range of 0–1000 psig?
A. decade box
B. squeeze bulb
C. function generator
D. dead-weight tester

CCST Answer

The correct answer is D, dead-weight tester. A dead-weight tester apparatus uses known traceable weights to apply pressure to a fluid for checking the accuracy of readings from a pressure gauge or pressure transmitter. Due to the force-multiplying properties of a dead-weight tester, these primary calibration instruments can typically be used to generate accurate test pressures from 15–10,000 psig.

By contrast, a squeeze bulb can only be used to generate pressures for calibration in the range of 0–500 inH2O (~18 psig).

A decade box is used to calibrate temperature transmitters and instruments and cannot be used for pressure calibration.

A function generator is a piece of electronic test equipment or software used to generate different types of electrical waveforms over a wide range of frequencies, and therefore cannot be used for pressure calibration.

Reference: Goettsche, L.D. (Editor), Maintenance of Instruments and Systems, Second Edition, ISA, 2005.

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