adccommunitymod (AutomationDirect) asked a question.
Created Date: November 01,2007
Created By: gregv7
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My project that I am working in is a label applicator. Parts list: Direct logic 205 PLC, DL250-1 CPU, D2-08ND3 input, D2-08TD-1 output, sure step motor, H2-CTRIO, power supply, Stp-Drv-4035 amplifier, C-more Micro graphic panel with an 8 button keypad bezel. As bags of product move down a conveyor, a photo eye detects the bags and then blows a label onto the bag. My labels come on a roll with a 1/4 inch gap between each label. I have a sensor that can detect the gap between each label. The sensor is mounted in a fixed position on the label machine. I am using a sure step motor to drive a knurled roller that will “pull� the backing paper through a dispensing plate. (A plate that separates the labels from the backing paper). There is a rubber friction roller that pinches the backing paper to the knurled roller to prevent slippage. There is a backing paper rewind spindle to take up the waste paper. I have all the necessary sensors and output coils wired and working. The stepper motor is wired and working. I used one of the example programs to test. My problem(s): I need to repeatedly position a label at the edge of the dispensing plate. I figure I need some sort of “label offset�. Then I need to step the motor a predetermined count based on the label length after each machine cycle. I would like to have the PLC learn the label length and store it in memory when a button is pushed on the control panel. I'm not sure on what pulse profile(s) to use. I have programmed a few projects before but nothing using a stepper motor. Any help and suggestions on the programming aspect of the project would greatly be appreciated. Thank you! Greg
Created Date: November 02,2007
Created by: allukes
If your sensor is detecting the label you are applying then you could use the built in homing routine (CTRIO) to detect the edge of the label and move it into position outside the normal ladder scan of the PLC. This would give you more repeatability and take care of any missing labels if that becomes a problem.
Created Date: November 02,2007
Created by: gregv7
Hi Allukes,
Thank you for the suggestion. I did what you said and set the CTRIO on a homing routine, rewired the label sensor to the CTRIO, set the parameters and it works great. I used the Run to Limit 1 at Frequency 1, then continue to Count at Frequency 2.
My only problem is the way it is set up now I can only position one size label on the machine without having to reprogram the CTRIO. Basically I need to figure out how to change the pulse count from the HMI.
Any suggestions?
Thanks again for you help!
Created Date: November 02,2007
Created by: allukes
Change your home move to stop after finding the edge or make a small offset move that would position it somwhere that would always be before the end of the smallest label. Then, immediately after the home move do a dynamic position move. This move you can change the distance via a register in the PLC. If you don't know what the label size is going to be , then have a special mode for measuring it automatically using the jog mode. You could even save that measurement under a part number to reload next time.
Created Date: November 07,2007
Created by: gregv7
Thanks Allukes,
I’ve been working on your suggestion. So Far I am able to get the two moves to work independently in the program as they are written in the examples. I thought I had both routines working together but as it turned out, the routine would only perform the dynamic move on the first cycle of the program. I have each move in its own stage. My biggest struggle is getting the C0 & C2 bits in the dynamic move to turn on & off at the proper time without any Human interface.
Thanks again for all your help,
Greg
Created Date: November 13,2007
Created by: Cap
Gregv7.
I am very interested in the outcome of your project.. In '00 I was up aginst a wall, and I chose to purchase an off the shelf labeler unit, and then cut it apart and put it back together the way I wanted it. I had problems convincing the mfg. of the unit to make software changes for me. They could not understand why such changes were nessasary.. It took a while but I finally got through to them.. But I then had to debug their software, and send boards back a forth across the country, and try to maintain a production plan!.. The stepper that they used was a Whedco and they have now been sold to GE, and support for the older stuff is kinda trickey.. And the mfg of the labeler does not use that drive type any more so future Software changes are out of the question!! GREAT..
Please keep the group posted as to your progress...CAP
Created Date: November 01,2007
Created by: gregv7
My project that I am working in is a label applicator.
Parts list: Direct logic 205 PLC, DL250-1 CPU, D2-08ND3 input, D2-08TD-1 output, sure step motor, H2-CTRIO, power supply, Stp-Drv-4035 amplifier, C-more Micro graphic panel with an 8 button keypad bezel.
As bags of product move down a conveyor, a photo eye detects the bags and then blows a label onto the bag.
My labels come on a roll with a 1/4 inch gap between each label. I have a sensor that can detect the gap between each label. The sensor is mounted in a fixed position on the label machine.
I am using a sure step motor to drive a knurled roller that will “pull� the backing paper through a dispensing plate. (A plate that separates the labels from the backing paper). There is a rubber friction roller that pinches the backing paper to the knurled roller to prevent slippage.
There is a backing paper rewind spindle to take up the waste paper.
I have all the necessary sensors and output coils wired and working.
The stepper motor is wired and working. I used one of the example programs to test.
My problem(s):
I need to repeatedly position a label at the edge of the dispensing plate. I figure I need some sort of “label offset�. Then I need to step the motor a predetermined count based on the label length after each machine cycle. I would like to have the PLC learn the label length and store it in memory when a button is pushed on the control panel.
I’m not sure on what pulse profile(s) to use.
I have programmed a few projects before but nothing using a stepper motor.
Any help and suggestions on the programming aspect of the project would greatly be appreciated.
Thank you!
Greg