Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Proportional Valve issue 1

Status
Not open for further replies.

Hakim Eng

Electrical
Joined
Dec 23, 2020
Messages
20
Location
DZ
Hello guys,
i have a linear hydraulic cylinder controlled by a plc through 4-20 mA proportional valve.
The whole hydraulic system composed of:
- proportional valve.
- blocking valve.
- pressure switch " to ensure oil presence"
- a position transducer.
when trying to move the cylinder up/down it works perfectly, but when trying to position the cylinder at an intermediate position the load goes donw by the inertia effect even the blocking EV is not energized at all ?!
Also, when powering-off the machine,i left the cylinder at initial position " up ", and when coming next day, i found the cylinder at the bottom position even though no power was present.


What cause the cylinder to change it's position with no Electro-valve energized?

Any help please
Thanks in advance
 
Sounds like your "blocking" valve isn't. Look into adding load control valves or pilot-operated check valves.
 
But the problem happens with several cylinder with the same hydraulic system i mentioned.
Could you please recommend me a documentation that describes the principal of operation of these proportional valves.
Thank you so much for your help
 
What cause the cylinder to change it's position with no Electro-valve energized?

Looks like gravity. The oil return line is open and the cylinder falls down by gravity
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top