11

One circuit employs direct control where a push-button directly activates the solenoid valve. The other circuit used a relay to activate the solenoid and this utilized indirect control.

Also, indirect control is commonly used for large cylinder and high-speed operations.

When the push button is pressed, electricity energized the relay coil K1 which causes the latching contact K1 to switch from normally open to close. This results in electrical flow across the solenoid and activates it.

We discussed on the two basic ways to actuate the hydraulic cylinder. Direct control activates the solenoid directly from a push-button while indirect control enables the solenoid by means of a relay.

The difference between the two methods of actuation is the use of a final control element in the indirect control.

This enables indirect control to operate larger hydraulic cylinders or at high-speed operation.

On the other hand, direct control is the simplest way to actuate a hydraulic cylinder.