Shop

Artificial Intelligence Notice: ISA prohibits the entry of any ISA intellectual property (“ISA IP”), including standards, publications, training or other materials into any form of Artificial Intelligence (AI) tools, such as ChatGPT. Additionally, creating derivatives of ISA IP using AI is also prohibited without express written permission from ISA’s CEO. In the case of such use, ISA will suspend a licensee’s access to ISA IP, and further legal action will be considered. Please review ISA's policies for Use of AI Tools, Intellectual Property and Terms and Conditions for further information.

Important Notice: Print books are temporarily unavailable. As of 12 August 2025, print books are no longer available for purchase on isa.org, but beginning 1 January 2026, they will be available for purchase through our publishing partner, Wiley. Kindle and ePub formats are still available via the links on each book's product page on isa.org. Learn More.

  • CCST
ISA Certified Control Systems Technician (CCST) program

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 is true of most pressure measurement methods?

A. They are not able to measure a small differential pressure.
B. The sensor matches the digital or analog signal conditioning and transmission.
C. They are sensitive to volume but not temperature.
D. They measure pressure by sensing the deflection of the diaphragm.

CCST Answer

The correct answer is D, they measure pressure by sensing the deflection of the diaphragm. For most pressure applications, changes in pressure are detected by the change in deflection of a measuring diaphragm.

The deflection is converted into an electrical signal (voltage) by a piezoelectric or capacitance device. The small electrical current is converted to a standard signal (e.g., 4-20 mA or a digital signal) by a transmitter. Therefore, answer B is not correct.

Answer A is not correct, because pressure sensors can measure very small pressure changes (inches of water) and in some cases, millimeters of water.

Pressure measurement devices are not affected by volume, since they are measuring force over an area only. Many pressure sensors are sensitive to temperature (capillary tubes are filled with fluids that can expand with temperature). Therefore, answer C is not correct.

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

Reader Feedback


We want to hear from you! Please send us your comments and questions about this topic to InTechmagazine@isa.org.



Like This Article?

Subscribe Now!

About The Author