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Unread November 10th, 2011, 11:53 AM   #16
leitmotif
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I think if we continue with this trend of comments ie unobtainium we are only going to create bitterness and resentment. Mistakes have been made on all sides I think.

Granted
1. there may be a language barrier

2. we need lots more information on what you are trying to do and what the process is all about. If we get this information we can help. Without it we can only guess at what this is all about and will only confuse the situation more.

Dan Bentler
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Unread November 10th, 2011, 11:04 PM   #17
mahdisan
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Thank you OZEE.
I do this project with FATEK plc one year ago.
Line speed is 10-80 m/min.in low speed cutter was worked accurate but in high speed cutter response was not good.(+\-10mm)
Measuring wheel encoder give 1 pulse per 1 mm.
DC motor rating power is 15KW at 180vdc and maximum 500 rpm .
motor speed feedback is dc tacho 60v/1000rpm.
motor to blade gearbox rate is 2.5/1
For blade position there is one encoder on the tacho at rear of DC motor.That is 360ppr.
DC motor manufactured by mitsubishi and drive by SSD parker.
I think FATEK is not good plc for this application.
I want used omron PLC for this project.(CP1H-XA40DT1)
Please help me


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Unread November 11th, 2011, 07:26 AM   #18
widelto
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No experience with Fatek PLC, but if you want I can send you a pdf copy of an allen bradley example from their web page that showns how a flying cutoff works. Is your fatek plc capable of doing motion control?, if answer is no then you have a problem and my recommendation is to change pc brand, like delta or allen bradley.
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Unread November 11th, 2011, 10:57 AM   #19
dskohio
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Not having a lot of specifics about how you are controlling the knife, it looks like it could be be a response time problem. At 80 meters/minute, it is 1.3 mm per millisecond.
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Unread November 12th, 2011, 09:06 AM   #20
mahdisan
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Hi
please tell me about unitronics plc for this application.
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Unread November 12th, 2011, 09:47 AM   #21
DamianInRochester
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Quote:
Originally Posted by mahdisan View Post
Hi
please tell me about unitronics plc for this application.
In order to assess whether Unitronics, or any other PLC would be good for this project, it would help if you can provide details, and maybe a sketch, of how you did the original system. Specifc parts numbers for everything. Simply stating SSD Parker and Mitsubishi still only narrows it down to 100 of different varients.

Possibly the problem isn't the Fatek, but more so your approach?



Unitronics is an Isreali product. If you are in Iran you may wish to make certain that it is something you could obtain without grief.
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Unread November 12th, 2011, 09:51 AM   #22
DamianInRochester
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Here is an application example off of Fatek's site. How close is this to your setup?

Application Example > High-speed counter
?A FBs-PLC can have up to 8 sets of 32bits high-speed counter. Among which, 4 sets are hardware high-speed counter (HHSC) whose counting frequency can reach 120KHz (MC)or 920KHz (MN) and can operate with 8 counting modes. The other 4 sets are software high-speed counter (SHSC) whose total input frequency can reach 10KHz and can operate with three counting modes. The high-speed counters can be used in the applications required high-speed processing and precision control.
?
Sample application?? The control of cutting machine with variable length
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Unread November 12th, 2011, 07:30 PM   #23
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I wonder if its this type?
and if he's doing this with a plc and not a motion
controller then 10mm error at 80m/min is awesome


especially the type he listed
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Unread November 13th, 2011, 04:14 AM   #24
mahdisan
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Dear friends
There is all unitronics products in iran and these products made in USA.
The rotary knife is working properly with fatek plc in low speed.
If you want i give you that programm.

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Unread November 13th, 2011, 04:20 AM   #25
shooter
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You will have to tell a little more, like what you are able to use and what you are thinking about, and please do not yell so loud i am not deaf, or please use other letters.
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Unread November 13th, 2011, 04:23 AM   #26
shooter
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yes please send the program, and what you are looking for.
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Unread November 13th, 2011, 07:05 AM   #27
DamianInRochester
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Quote:
Originally Posted by mahdisan View Post
Dear friends
There is all unitronics products in iran and these products made in USA.
The rotary knife is working properly with fatek plc in low speed.
If you want i give you that programm.
Are we talking about the same Unitronics?
http://www.unitronics.com/Content.aspx?page=Profile
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Unread November 13th, 2011, 07:22 AM   #28
mahdisan
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Your are right
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Unread November 13th, 2011, 07:38 AM   #29
DamianInRochester
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Quote:
Originally Posted by mahdisan View Post
Thank you OZEE.
I do this project with FATEK plc one year ago.
Line speed is 10-80 m/min.in low speed cutter was worked accurate but in high speed cutter response was not good.(+\-10mm)
Measuring wheel encoder give 1 pulse per 1 mm.
DC motor rating power is 15KW at 180vdc and maximum 500 rpm .
motor speed feedback is dc tacho 60v/1000rpm.
motor to blade gearbox rate is 2.5/1
For blade position there is one encoder on the tacho at rear of DC motor.That is 360ppr.
DC motor manufactured by mitsubishi and drive by SSD parker.
I think FATEK is not good plc for this application.
I want used omron PLC for this project.(CP1H-XA40DT1)
Please help me

If +/- 10mm is too much variance for you, the your feedback of 1 pulse per mm is pretty low resolution. That is also a pretty low resolution for your cutter position.

From my standpoint, you shouldn't be looking for a PLC at all. You should have a high speed programmable servo with an auxilliary encoder input to track the measuring wheel. I would look to increase the resolution of the tracking wheel as well to eliminate jitter in a master/follower setup.

Based on what you have given us, I think your system is probably working as well as it can.
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Unread November 13th, 2011, 08:01 AM   #30
Steve Bailey
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I agree with the assessment that you are getting about as much performance as you can expect out of your PLC. Consider this: At 80 meters/minute, the web is traveling at 1.3 mm/millisecond. If your PLC scan time is 10 milliseconds, the web is moving 13.33 mm each PLC scan. Once per scan is the fastest you can update any commands the PLC sends to the drive. That's why you need a dedicated motion controller.

Does your system simply try to maintain the knife speed at a ratio to the web speed or do you vary the ratio so as to match the blade speed to the web speed while the knife makes the cut? If the latter, is the knife motor large enough to provide the torque required to accelerate the knife cylinder at the higher web speed?
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