Which unit is used for the pneumatic control signal?

Which unit is used for the pneumatic control signal?

• A. PSI
• B. Volts
• C. Amps
• D. Ohms

Answer: (A)

Pneumatic control signals are carried by air pressure, so the unit that describes the signal is a pressure unit. Pounds per square inch (PSI) is the standard way to express that pressure in many industrial systems, making it the appropriate unit for a pneumatic signal. The other units measure electrical quantities—volts for electrical potential, amps for current, and ohms for resistance—and don’t describe air pressure. In practice, a pneumatic controller might use a 0–20 psi signal to position a valve, though some systems may use kilopascals or bar in other regions.

Pneumatic control signals are carried by air pressure, so the unit that describes the signal is a pressure unit. Pounds per square inch (PSI) is the standard way to express that pressure in many industrial systems, making it the appropriate unit for a pneumatic signal. The other units measure electrical quantities—volts for electrical potential, amps for current, and ohms for resistance—and don’t describe air pressure. In practice, a pneumatic controller might use a 0–20 psi signal to position a valve, though some systems may use kilopascals or bar in other regions.