Which statement correctly describes a 3/2 valve and a 5/2 valve?

Which statement correctly describes a 3/2 valve and a 5/2 valve?

• A. A 3/2 valve has three ports and two positions; used to control a double-acting cylinder.
• B. A 5/2 valve has two ports and two positions.
• C. A 3/2 valve has two ports and three positions.
• D. A 5/2 valve has five ports and two positions; used to control a double-acting cylinder.

Answer: (D)

In pneumatic valve naming, the two numbers show how the valve is built and how it operates: the first number is the number of ports, and the second number is the number of positions. A five-port, two-position valve has five ports—typically a supply port, two work ports that connect to a double-acting cylinder, and two exhaust ports. The two distinct positions provide two different flow paths, allowing air to be directed to either extend or retract the double-acting cylinder. This setup is what enables control of a double-acting cylinder, since both sides of the cylinder are pressurized independently to produce motion in either direction. In contrast, a three-port two-position valve has three ports (supply, one exhaust, and a single cylinder port) and is commonly used with a single-acting cylinder, where only one direction is actively pressurized and the other is vented. The statements describing a five-port valve as having two ports are incorrect, as are the statements about a three-port valve having three positions or a five-port valve having two positions but only one supply. The accurate description is that a five-port two-position valve has five ports and two positions, and it’s used to control a double-acting cylinder.

In pneumatic valve naming, the two numbers show how the valve is built and how it operates: the first number is the number of ports, and the second number is the number of positions. A five-port, two-position valve has five ports—typically a supply port, two work ports that connect to a double-acting cylinder, and two exhaust ports. The two distinct positions provide two different flow paths, allowing air to be directed to either extend or retract the double-acting cylinder.

This setup is what enables control of a double-acting cylinder, since both sides of the cylinder are pressurized independently to produce motion in either direction. In contrast, a three-port two-position valve has three ports (supply, one exhaust, and a single cylinder port) and is commonly used with a single-acting cylinder, where only one direction is actively pressurized and the other is vented.

The statements describing a five-port valve as having two ports are incorrect, as are the statements about a three-port valve having three positions or a five-port valve having two positions but only one supply. The accurate description is that a five-port two-position valve has five ports and two positions, and it’s used to control a double-acting cylinder.