×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

PID loop tuning

PID loop tuning

PID loop tuning

(OP)
Hi, we're trying to control a modulating steam valve to a using a controller that seems to have four tunable terms. Here are the current values:
PbH         16.6
Intr        65
Rset        50
Driv        OFF
Question is, what are the four terms? I recognize proportional band, integral, and derivative, but what's rset? I thought reset was the inverse of the integral term? Any thoughts? TIA!

Fran McConville

RE: PID loop tuning

Initial (reset ) value?

<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032

RE: PID loop tuning

Search for PID and Zigler Nichols.
PB is proportional band, a.k.a. proportional or gain.
I is Integral a.k.a. reset
D is Derivative a.k.a. rate

John

RE: PID loop tuning

(OP)
Thanks folks, I determined that the Rset is a "manual reset" parameter that this controller features in addition to the P, I, and D parameters. But don't ask me what it actually does...

Fran McConville

RE: PID loop tuning

P = proportional or gain, the one you got from the equation of response graph

I = Integral, for minimizing the offset.

D = Derivative, for high respon and less dead time

rset = set point value

the integral and derivative constant is derived from the ziegler nichols, ciancone, and many method

Regards,
Napz
http://www.enginework.net

RE: PID loop tuning

Manual reset is same as bias. For a proportional only controller, it is the output of the controller when there is no there is no error (so process value is same as set point). If you have for example a level controller that acts on a control valve in the liquid outlet line, this control valve will be partially open when there the liquid level is at the setpoint. You can have the integral term (or reset) of the PID controller handle this, or this is done by the bias term (or manual reset).  

See http://www.jashaw.com/pid/description.htm

RE: PID loop tuning

(OP)
Bias - that's it! Thanks Guidoo.

Fran McConville

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!


Resources