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#201855 06/28/11 07:30 PM
Joined: Sep 2002
Posts: 37
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Member
I am trying to automate a 36" wide belt feed belt grinder for a friend.
It has a delta S1 vfd running the feeding belt with reversing ability.
We are trying to put some sort of control on either side of the machine which will sense when the steel plate material finishes the forward pass, stop the feed belt, reverse the feed belt and repeat. I am thinking about a wheel limit switch with NC/NO contacts.
The VFD has an input for manually reversing the unit via a 3 wire input.
Common ground to both:
Input 1---open=stop closed=run forward
Input 2---open=stop closed=run reverse

Page 96 of this PDF
http://www.delta.com.tw/product/em/drive/ac_motor/download/manual/VFD-S_manual_en.pdf

Anybody have any suggestions?

Joined: Jul 2004
Posts: 783
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Member
I see the need for four limit switches. Two on each side of the machine along the centerline of the grinder. Label them Left far, Left edge, Right edge, and Right far. Left and Right edge tells you the plate has cleared the grinder.

Left far PLUS Left edge tells you the plate is off the grinder to the left.

Right edge PLUS Right far tells you the plate is off the grinder to the right.

LF & LE & NOT (RE) = Start belt feed to the Right

RF & RE & NOT (LE) = Start belt feed to the Left

LE & RE = Plate in grinder, direction UNKNOWN

You also need manual belt drive controls to load the plate in the grinder, E-stops for operator safety. some sort of counter or limit switch when the plate is done. You will need to set the slew rate and time when reversing the belt direction. Also auto/manual selector, possibly a status light to tell you what mode it is in. How do you set the grinding height.

This sounds like a small PLC would help with the run logic.


Joined: Mar 2004
Posts: 947
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twh Offline
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A programmable relay would probably have enough inputs and outputs.

Joined: Jul 2004
Posts: 783
L
Member
Originally Posted by LarryC
I see the need for four limit switches. Two on each side of the machine along the centerline of the grinder. Label them Left far, Left edge, Right edge, and Right far. Left and Right edge tells you the plate has cleared the grinder.

Left far PLUS Left edge tells you the plate is off the grinder to the left.

Right edge PLUS Right far tells you the plate is off the grinder to the right.

LF & LE & NOT (RE) = Start belt feed to the Right

RF & RE & NOT (LE) = Start belt feed to the Left

LE & RE = Plate in grinder, direction UNKNOWN

You also need manual belt drive controls to load the plate in the grinder, E-stops for operator safety. some sort of counter or limit switch when the plate is done. You will need to set the slew rate and time when reversing the belt direction. Also auto/manual selector, possibly a status light to tell you what mode it is in. How do you set the grinding height.

This sounds like a small PLC would help with the run logic.


REVISIONS

Left far AND NOT Left edge tells you the plate is off the grinder to the left.

NOT Right edge AND Right far tells you the plate is off the grinder to the right.

LF AND NOT LE AND NOT RE = Start belt feed to the Right

RF AND NOT RE AND NOT (LE) = Start belt feed to the Left

LE AND RE = Plate in grinder, direction UNKNOWN

ASSUMPTIONS

1) Limit switch is made only when the plate is actuating switch.

2) This logic only auto reverses the belt drive. It does not contain START or STOP functions. Those need to be added seperately.


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