Alan

I can't connect to the shaft. I need something that roll on the reel and
count the length wile the material is rolling.
I think a picture is best and I will take a photo on Sunday so you can see
the feeding mechanism.

Tal

-----Original Message-----
From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On
Behalf Of Alan B. Pearce
Sent: Thursday, September 11, 2003 11:24 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]: Length measurement


> I have many suppliers and of course many kind of materials that weight
> differently. but I know that all of it are 50m reels.
> so I have to stick to the length method. as I say before a rubber pinch
> roller encoder will do the job. now I have to find a pic counter to
> translate it to digits and readable data.

As I understand it you know the following: -

1. Minimum length of material on the roll.

2. Material thickness (varies for different materials, but is known or can
be measured for each one)

Can you have a turns counter on the roll, because from a starting point of a
full roll, it seems to me that you just want to know to a reasonable
approximation the amount left. From the thickness and the turns count it
should not be too hard for a calculation to be made as to how much is left.
because of the varied materials used, the operator will need to tell the
electronics which material is loaded, but this could be done from a menu.
Using suitable EPROM tables new menu items could be downloaded as new
materials get used. You quoted up to 500mm accuracy in a previous message,
and I would expect to get within that fairly readily.

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