Encoder(maybe) issue.

[locotumbler]

a little back story on my machine.
It is a cut to length machine running via a Zeta 6104 controller. the encoder is operated by the 1/2 round wire being pulled over the steel shaft. the downward force is generated a spring loaded lever. the actual part pushing down on the wire is a bearing with a grove in it so as to keep the wire in place.

Problem I have is that over the run and when i shut it down and run again is that the wire shrinks in length so I have to go in and increase the total number of counts in order to achieve the correct length.
the encoder is a 1000ppr encoder. the shaft is .315" in diameter and the parts are 13.17" and 13.5" in length.

for the 13.17" rod i have my counter set to 54030
for the 13.50" rod i have my counter set to 55450

I have encountered issues before where i start losing counts on an encoder but when that happened my rod length began to grow as it needed to pay out more to meet the count level. Have any of you ever encountered an issue where an encoder causes parts to shrink in size. i.e. its putting our MORE pulses than before?

the encoder model E151000A865

 

[gclshortt]

Breaking the information down, lets see what the counters should be set for to achieve 13.17 and 13.5" in length.
- Shaft is .135 in diameter = 3.14 x .135" = 0.4239" in circumference
- One revolution of the shaft is 0.4239" length
- 13.5" / 0.4239" = 31.847 rotations x 1000 ppr = 31847
- 13.17 / 0.4239" = 31.068 rotations x 1000 ppr = 31068

Currently you have the counters set for 55450 and 54030.
If I did the math correctly, it looks like you have allot of slip between your shaft/encoder and the piece that you are measuring.

Regards,

 

[kjacoby]

Garry, the Shaft is .315" in diameter. You put in .135. I did a quick search to see if the .135 shaft size is truly correct, and the .315 is wrong, but i can't find anything.

- Shaft is .315 in diameter = 3.14 x .315" = 0.9896" in circumference
- One revolution of the shaft is 0.9896" length
- 13.5" / 0.9896" = 13.64185 rotations x 1000 ppr = 13642
- 13.17 / 0.9896" = 13.30838 rotations x 1000 ppr = 13308

I just seen Bernies Reply, that would put this at,
54567 and 53233

Kenneth

 

[bernie_carlton]

I'm assuming that you are counting a quadrature encoder in *4 mode.

 

[locotumbler]

this controller you don't setup the counting but as it will decrease the count is the encoder is rotated backwards so i'm thinking so as its using a and a-, b and b-, z and z-.

 

[locotumbler]

Del wire
def wire

comexs1
comexc1
comexp1
outen00000000xxxxxxxxxxxxxxxxxxxxxxxx
drive0
encpol1
enc1
drive1
ma0
mc0
scale0
dres25000
eres4000
enc1
epm1
emovdb1
epmdb3
epmg500
epmv0.2500
a0.4000
ad0.5000
v2.5000
var2=0.0
var3=0.0
var4=0.0
var20=0.0
dclear0
dpcur1,0
dwrite "select part#"
dpcur2,0
dwrite "2470 2556 2471 2887"
var62=dreadf
if(var62=1.0)
d54030
nif
if(var62=2.0)
d55450
nif
if(var62=3.0)
d39482
nif
if(var62=4.0)
d55643
nif
dclear0
dpcur1,0
dwrite "enter # of tubes to run"
var2=dread
$main
dclear0
dpcur1,0
nif
dwrite "please ensure press is ready to run cont"
dpcur2,0
dwrite "press cycle start when ready to start"
wait(in=b1)
dclear0
dpcur1,0
dwrite "running please wait"
outenxxx10xxxxxxxxxxxxxxxxxxxxxxxxxxx
repeat
outenx1xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
go1
l
if(in=bxxxxxxx1)
wait(mov=b0)
outenxxx01xxxxxxxxxxxxxxxxxxxxxxxxxxx
dclear0
dpcur1,0
dwrite "change buffing wheel"
dpcur2,0
dwrite "when complete press f1"
var30=dreadf
wait(var30=1.0)
outenxxx10xxxxxxxxxxxxxxxxxxxxxxxxxxx
dclear0
dpcur1,0
dwrite "running"
outenxxxxx1xxxxxxxxxxxxxxxxxxxxxxxxxx
var30=0.0
wait(in=bxxxxxxx0)
outenxxxxx0xxxxxxxxxxxxxxxxxxxxxxxxxx
nif
if(in=bxxxx1)
goto cutoff
nif
if(mov=b0)
goto cutoff
nif
if(in=bxxxxxxxxxx1)
wait(mov=b0)
outenxxx01xxxxxxxxxxxxxxxxxxxxxxxxxxx
dclear0
dpcur1,0
dwrite "good bin full"
dpcur2,0
dwrite "replace tube and press f1 when clear"
var15=dreadf
wait(var15=1.0)
outenxxx10xx1xxxxxxxxxxxxxxxxxxxxxxxx
wait(in=bxxxxxxxxxx0)
var4=var4+1.0
if(var2=var4)
goto count
nif
goto cutoff
nif
if(in=bxxxxxxxxxxx1)
wait(mov=b0)
outenxxx01xxxxxxxxxxxxxxxxxxxxxxxxxxx
dclear0
dpcur1,0
dwrite "bad bin full"
dpcur2,0
dwrite "replace tube and press f1 when clear"
var17=dreadf
wait(var17=1.0)
outenxxx10xx1xxxxxxxxxxxxxxxxxxxxxxxx
wait(in=bxxxxxxxxxxx0)
var20=var20+1.0
goto cutoff
nif
ln
$cutoff
nif
l
if(mov=b0 and in=bxxxx1)
outen1xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
wait(in=bx10)
outenx01xx0xxxxxxxxxxxxxxxxxxxxxxxxxx
wait(in=bxxxxx1)
outen0xxxxxx0xxxxxxxxxxxxxxxxxxxxxxxx
wait(in=bx01)
outenxxxxxx1xxxxxxxxxxxxxxxxxxxxxxxxx
wait(in=bxxxxxx1)
outenxx0xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
outenxxxxxx0xxxxxxxxxxxxxxxxxxxxxxxxx
var3=(var3+1.0)
goto count
nif
if(in=bxxxxxxxxxx1)
wait(mov=b0)
outenxxx01xxxxxxxxxxxxxxxxxxxxxxxxxxx
dclear0
dpcur1,0
dwrite "good bin full"
dpcur2,0
dwrite "replace tube and press f1 when clear"
var15=dreadf
wait(var15=1.0)
outenxxx10xx1xxxxxxxxxxxxxxxxxxxxxxxx
wait(in=bxxxxxxxxxx0)
var4=var4+1.0
if(var2=var4)
wait(mov=b0)
goto count
nif
goto cutoff
nif
if(in=bxxxxxxxxxxx1)
wait(mov=b0)
outenxxx01xxxxxxxxxxxxxxxxxxxxxxxxxxx
dclear0
dpcur1,0
dwrite "bad bin full"
dpcur2,0
dwrite "replace tube and press f1 when clear"
var17=dreadf
wait(var17=1.0)
outenxxx10xx1xxxxxxxxxxxxxxxxxxxxxxxx
wait(in=bxxxxxxxxxxx0)
var20=var20+1.0
goto cutoff
nif
if(in=bxxxxxxx1)
wait(mov=b0)
outenxxx01xxxxxxxxxxxxxxxxxxxxxxxxxxx
dclear0
dpcur1,0
dwrite "change buffing wheel"
dpcur2,0
dwrite "when complete press f1"
var30=dreadf
wait(var30=1.0)
outenxxx10xxxxxxxxxxxxxxxxxxxxxxxxxxx
dclear0
dpcur1,0
dwrite "running"
outenxxxxx1xxxxxxxxxxxxxxxxxxxxxxxxxx
var30=0.0
wait(in=bxxxxxxx0)
outenxxxxx0xxxxxxxxxxxxxxxxxxxxxxxxxx
nif
nif
ln
$count
nif
dclear0
dpcur1,0
dwrite "total parts"
dpcur1,12
dvar3,5,,0
dpcur1,18
dwrite "#of bad tubes"
dpcur1,32
dvar20,5,,0
dpcur2,0
dwrite "#of good tubes"
dpcur2,15
dvar4,5,,0
dpcur2,21
dwrite "working to"
dpcur2,32
dvar2,5,,0
until(var2=var4)
outen00000000xxxxxxxxxxxxxxxxxxxxxxxx
s1
end

 

[locotumbler]

attached is the entire code for the controller.

 

[gclshortt]

Thanks Kenneth
I believe we still have some slip.
The counters should be set for 54567 and 53233
But are set for 55450 and 54030
Locotumbler, is it possible that the piece being measured is moving backwards with respect to the encoder? This would account for the extra counts.

Just a thought,

 

[locotumbler]

What do you mean moving backwards in respect the encoder? I know if the encoder is going on direction and stops and before it cuts off you manually move the encoder the other direction it slowly move it forward in order to add the counts you just removed by manually moving the encoder in reverse.

 

[kamenges]

Just to make sure I understand...

When you start after a shutdown, you have to increase the counts to get the correct length. Do you have to decrease the counts back down to where you started during the run?

Keith

 

[locotumbler]

I've never had to decrease counts. I have ran this machine for about 7 years without issue. Now the last month I've been having issues. I have since replaced the encoder with a direct replacement and still having issues.


The parts never had variation and now I have up to .020" variation during the runs even with increasing the counts when they start out short. It's shielded cable on the encoder and the cable the encoder plugs into.

 

[locotumbler]

The .020" variation comes in at times and other times it will run 6k parts without any variation.

 

[keithkyll]

I suspect the power supply inside the Zeta 6104. Bad caps, temperature sensitive, on the edge. Measure the 5 volts it supplies for the encoder. Put a scope on it.
Is the encoder directly connected to the Zeta?

 

[locotumbler]

It is connect via a db9 connection. I know a scope can be hooked up to an encoder but I've never done it and my exhaustive searchs of the Internet haven't shown up anything on how to connect it.

 

[Doug-P]

It is connect via a db9 connection. I know a scope can be hooked up to an encoder but I've never done it and my exhaustive searchs of the Internet haven't shown up anything on how to connect it.

Perhaps one of these? http://www.amazon.com/Electronics-S..._UL160_SR160,160_&refRID=0T32ZN5XZVCJ5WVSNRN6