Directional vs. Proportional Solenoid Valves

Control methods used by the IHP24

Understand the different control methods

The Intelligent Hydraulic Positioner (IHP24) range from Val Controls has the possibility to control the actuator using two methods: either using directional solenoid valves or proportional solenoid valves. The positioner is also easily adapted to any already existing control systems or other designs.

The desired position of the valve is sent to the IHP24 via the 4-20mA control loop or a communication protocol. The actual position is measured by the IHP via a potentiometer or a 4-20mA sensor. The set point and position signal is compared and the actuator is moved to the requested position.

Feature	Directional Solenoid Valve	Proportional Solenoid valve
IHP24 compatabible	Yes	Yes
Control signal	4-20mA	4-20mA
Control Method	Binary (open/closed)	Variable (any point between fully open/closed)
Fluid Flow Control	Controls the direction of fluid flow	Controls the flow rate of fluid
Flow Control Accuracy	Not very precise - accuracy up to 1%	Highly precise - accuracy better than 1%
Cost	Inexpensive	Expensive
Maintenance	Low maintenance due to low complexity	High maintenance due to high complexity
Applications	On/off applications e.g., switching between two fluid circuits	Applications requiring precise fluid flow control e.g., hydraulic systems

Directional solenoid valves

Directional are typically binary valves, meaning that they have only two states: open or closed. When the valve is open, fluid can flow through it in one direction, and when it is closed, no fluid can flow through it. Directional solenoid valves are avialable in a variety of configurations, including 2-way, 3-way and 4-way valves. In the schematic shown below, a 4-way configuration is given as example.

The Intelligent Hydraulic Positioner (IHP24) can use 1-4 24VDC directional solenoid valves for control of the hydraulic actuator. The IHP24 is designed so it can use any directional solenoid valve on the market. The unit will automatically adapt the regulator to the performance of the complete system, during an automatic calibration.

Image: schematic of a hydraulic system with a 4-way directional solenoid valve

Proportional solenoid valves

Proportional solenoid valves are a type of solenoid valve that is designed to provide precise and accurate control over the flow of fluid through the valve. Unlike directional solenoid valves, which are binary valves that have only two positions (open or closed), proportional solenoid valves can control the flow rate of fluid at any point between fully open and fully closed.

The intelligent Hydraulic Postioner (IHP24) can use 1-2 4-20mA proportional valves for control of the hydraulic actuator. The IHP24 is designed so it can use any proportional valve on the market. The unit will automatically adapt the regulator to the performance of the complete system, during an automatic calibration.

One of the main advantages of proportional solenoid valves is their ability to provide precise and accurate control over the flow of fluid, which makes them well-suited for applications that require tight control over fluid flow rates. They are also relatively easy to install and operate, and can be integrated into a range of different control systems. Proportional solenoid valves are typically more expensive than directional solenoid valves, and may require more maintenance due to their more complex design and control mechanisms.

Image: schematic of a proportional solenoid valve