Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Proportional Valve issue

Proportional Valve issue

Proportional Valve issue

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

RE: Proportional Valve issue

Sounds like your "blocking" valve isn't. Look into adding load control valves or pilot-operated check valves.

RE: Proportional Valve issue

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

RE: Proportional Valve issue

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

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close