Sun's Proportional Valves Enable Meter-in and Meter-out in Motion Control Circuits

Valve Details

FMDB and FMDA direct acting cartridges block the supply port (port 1) in the de-energized position while directing flow to tank via port 2 to port 3. No throttling is present in the 2 to 3 direction.

Model FMDB offers lower flow capacity with full flow in the port 2 to 3 direction and is available in three flow ranges, from 1.6 to 6 gpm (6,1 to 23 L/min.).
Model FMDA offers higher flow capacity and improved resolution in the 1 to 2 flow direction while sacrificing flow capacity in the 2 to 3 flow direction and is available in four flow ranges, from 1.6 to 9 gpm (6,1 to 34 L/min.). FMDA's are designed for use in Sun's cushion lock circuit (shown below) where the return flow has an independent path to tank.

Creating 3-Position, 4-Way Circuits

New Electro-Proportional Throttling Valves Shown to the right, two FMDB cartridges are used to create a 3 position, 4-way proportional valve with meter-in control. Line Mount: FMDBMCN912-U9A ISO 03: FMDBMCN224-U7M

Benefits of this circuit arrangement include:

• Using separate meter-in devices allows system control gain to be optimized for differential cylinder flow requirements.
• All Sun standard coil and control options may be utilized.

Control with Counterbalance Cartridges In this example, two FMDB cartridges are used in series with two counterbalance valves where return flow takes place through the directional valve. Meter-out Line Mount: CBCALHN-YEJ ISO 03: CBCALHN-Z6Q Meter-in Line Mount: FMDBMCN912-U9A ISO 03: FMDBMCN224-U7M

• Separating the meter-in and meter-out control allows optimization of motion control solutions without having to create special spools.
• Leakage characteristics allow positive load locking.
• With FMDB only: Counterbalance valves provide full flow relief, dependent on the 2 to 3 flow capacity of the FMDB valve.

Meter-in, Meter-out Control in Sun's Cushion Lock Circuit Two FMDA cartridges can be used to create a 3 position, 4-way proportional valve with both meter-in and meter-out control, as shown in Sun's cushion lock circuit to the right. Meter-out Line Mount: CBCALHN-EMJ ISO 03: CBCALHN-U7U Meter-in Line Mount: FMDAMCN912-U9A ISO 03: FMDAMCN224-U7M

• Circuit flushing and replenishment from using the counterbalance valves in series along with anti-cavitation protection via the check valves.
• Improved resolution by using the FMDA cartridges and directing the return flow independently to tank.