Textile Mill Warper ramping issues

RCBrooks69 · Mar 30, 2017

I'm having some issues with one of our warpers. I'll just put the issue and and see if anyone can help narrow it down for me. As the yarn pulls in from the smaller spools it all collects together on a giant spool called a beam. So that being said, if a string of yarn breaks they must stop the machine to tie it back in before the beam can continue rolling. Once the machine is started back up the ramp up highly overshoots our set point. the set point is 800ypm (yards per minute), but the machine is ramping up to or over 1350ypm causing the yarn to break continually stopping the machine creating a vicious cycle of stopping and starting. Can anyone help with a possible answer as to what I can add or change in the program to decrease the abrupt ramp while keeping the yarn from dragging the ground from a slow ramp?

fredz0003 · Mar 30, 2017

Perhaps there's is something wrong about the setpoint scaling. What happens when your SP is set to 400 ypm? Do you see a decrease in actual?

Does the overshoot of 1350ypm stays constant, and then comes down to the SP?

Here's an idea of a ramp function. https://support.industry.siemens.co...via-a-ramp-function-generator-?dti=0&lc=en-WW

RCBrooks69 · Mar 30, 2017

ramping issue

it passes the set point and works it's way up toward 1350ypm give or take, then it drops down to the set point after the initial startup ramp. it doesn't consistently stay around 1350ypm.

James Mcquade · Mar 30, 2017

just a guess on my part.

is the ramp up speed set in the drive?
when you start the drive, the internal setting of the drive may be at 1350 and that's where it tries to go.
in the mean time, the plc tells the drive to goto the slower speed.

or

the plc controls the ramp up and the reaction time is too slow and you go to the 1350 speed (approx.) before any speed correction is done.

Like I said, just a guess on my part.

james

RCBrooks69 · Mar 30, 2017

I'm feeling more toward the reaction time. I didnt write the ladder, a man before me set it up. I'm trying to figure out how to put a cap on how high the overshoot max is. If I have a set max of 800ypm in the program, there has to be a way I can ramp up without dragging yarn and super overshooting the set point.

Steve Bailey · Mar 30, 2017

Has it ever worked correctly? If yes, what changed?

RCBrooks69 · Mar 30, 2017

the ramp speed is set up in the program

RCBrooks69 · Mar 30, 2017

It hasn't always worked correctly from what I understand...

JRW · Mar 30, 2017

What brand of drive/model?
I've worked on a few of those machines but it's been awhile. Doesn't it have a delivery roll that is the master to the beam drive(s)? Then the beam drive is adjusted by a diameter calculator.

GaryS · Mar 30, 2017

it sounds to me like the PID control is running while the motor is stopped
when you do that the PID keeps increasing the speed command until it sees feedback = set point
try this when the motor is stopped set the PID control in manual mode with a manual speed command of 0. that way the PID will calculate the command to the motor as 0 then when it is set back to auto control it will start the command at 0 and work it's way up.
you could also set the upper limit to the command you speed you want and prevent overshoot

RCBrooks69 · Mar 30, 2017

JRW said:
What brand of drive/model?
I've worked on a few of those machines but it's been awhile. Doesn't it have a delivery roll that is the master to the beam drive(s)? Then the beam drive is adjusted by a diameter calculator.

This is a West Point warper with a dura pulse drive running Productivity Suite 3000 software. It has a press roll behind the beam operated by hydraulics and pneumatics. I came from the metal forming industry, so this type of plc logic is a bit different from what I am used to.

fredz0003 · Mar 30, 2017

James Mcquade said:
just a guess on my part.

is the ramp up speed set in the drive?
when you start the drive, the internal setting of the drive may be at 1350 and that's where it tries to go.
in the mean time, the plc tells the drive to goto the slower speed.

or

the plc controls the ramp up and the reaction time is too slow and you go to the 1350 speed (approx.) before any speed correction is done.

Like I said, just a guess on my part.

james

An easy way to find out where the problem lies if is in the PLC or the drive. Is to setup a trend, monitor reference speed, start input, and actual drive RPM when you start the machine.
If you note the reference speed ramping up to the SP in the PLC, but the drive actually overshooting then you know for sure something is not setup right in the drive.
If you note the overshoot in the speed reference sent to the drive then you need to tune the PID controller properly in the PLC.

Can you send screenshots or PDF of the logic pertaining to drive signals?

RCBrooks69 · Mar 30, 2017

fredz0003 said:
An easy way to find out where the problem lies if is in the PLC or the drive. Is to setup a trend, monitor reference speed, start input, and actual drive RPM when you start the machine.
If you note the reference speed ramping up to the SP in the PLC, but the drive actually overshooting then you know for sure something is not setup right in the drive.
If you note the overshoot in the speed reference sent to the drive then you need to tune the PID controller properly in the PLC.

Can you send screenshots or PDF of the logic pertaining to drive signals?

If you have a copy of the Productivity Suite 3000, I could email a copy of the file

kwade · Mar 30, 2017

fredz0003 said:
An easy way to find out where the problem lies if is in the PLC or the drive. Is to setup a trend, monitor reference speed, start input, and actual drive RPM when you start the machine.

PAC 3000 has Word and Bit Histograms.
Word Histogram supports monitoring of 3 numeric tags.
Bit Histogram supports monitoring of 6 binary tags.

You can have both types of histograms running simultaneously - just have a way to indicate start/stop synchronicity.

fredz0003 · Mar 30, 2017

RCBrooks69 said:
If you have a copy of the Productivity Suite 3000, I could email a copy of the file

Sure thing. I can take a quick look. I pm you my email.

Textile Mill Warper ramping issues

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