The post AutoQuiz: How to Calculate Steady State Gain for a Standard Pneumatic Instrument Loop first appeared on the ISA Interchange blog site.
This automation industry quiz question comes from the ISA Certified Control Systems Technician (CCST) program. Certified Control System Technicians calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables. Click this link for more information about the CCST program.
a) 0.06 psig/unit
b) 0.07 psig/unit
c) 0.08 psig/unit
d) 0.12 psig/unit
e) none of the above
The correct answer is A, 0.06 psig/unit.
Gain is defined in control theory as the change in input divided by the change in output. In this case, the gain can be calculated as follows:
Gain = (full range change in input) / (full range change in output)
= (15 psig – 3 psig, for a pneumatic loop) / 200 units of change
= (15 – 3) / 200
= 12 / 200
= 0.06 psig/unit
Reference: Goettsche, L.D. (Editor), Maintenance of Instruments and Systems, 2nd Edition
Source: ISA News