Analog 12V Valve Control

[S4M]

Hey Everyone!

I have my first teensy on the way (3.2) and I was hoping to get a little bit of advice.

I am planning to use the Teensy to control two 12V Hydraulic solenoids. Bottom of page 35 in manual for PVEH.
http://files.danfoss.com/documents/pve%20series%204%20electrical%20actuating%20module%20for%20pvg%2032%20100%20120%20and%20pvhc%20technical%20information%20manual/520l0553.pdf

I have a regulated 12V source available.
The solenoids are at 0 at 0.5 * SupplyV
A-port ↔ B-port 0.25 → 75 * SupplyV

My thoughts were:
PWM outputs set to 187500Hz
Two logic level N MOSFETs on two Teensy pins
RC filter after each MOSFET with R=1K and C=100nF

This will give me a settling time of 0.00023 seconds and a ripple of 0.159v (~1%).

Does this sound like a good approach?

Thanks,

Sam

 

[S4M]

Got this sorted!

Solenoid can use PWM

 

[instrumentek]

Hi;

I work on hydraulic solenoids like this quite often, And most actually respond better to PWM. As the hydraulic solenoids age / get dirty the develop internal friction and a dead band. The off-on pulse on a PWM signal helps the system deal with the internal friction. Quite often hydraulic solenoid amplifiers will even have a dither frequency adjustment. Alot of time solenoids will even have a recommended frequency where they work best. On page 25 of the manual you listed they have some recommended frequencies. I've specifically ran into solenoids we thought where bad but the problem turned out to be a amplifier putting out the wrong frequency, Exact same measurable current, just a different frequency.

 

[S4M]

Thanks instrumentek!

I think I drive them with a h-bridge motor driver with the Teensy set to the recommended frequency.