PLC Expert needed

Doylen

Member
Doylen
Join Date
Dec 2007
Location
Virginia
Posts
46
We have AB 5/01 Processor.
We are detecting part with Cognex Scanner (camera).

We need your PLC Programming help!
We have "J" shaped parts magazine with index cylinder.
At mid-bottom section, Cognex scanner scans the part for the wrinkle and alerts to PLC either good or bad.
When I get "bad" part signal from camera, I:1/8, I need to count 3 cycles before I can reject. Another words, reject bin is located at 3rd cycled index position from scanning area.
Anyone can help?o_O
 
I would use a bit shift left sequence that was enabled by your "reject" signal and "shifted" via your index command. When the appropriate bit is true, i.e. it is at the reject station, you can have the logic then dump the part. I guess you could do this with a counter as well, enable it with the reject detection, count the index pulses, fire the reject at "3" and reset the counter.

Hope this helps

Scott
 
Thanks for kind answer, ScottC.
But the problem with counter we have, for instance, within the reject counter less than 3, if we get another reject signal (another part) from scanner.
We've tried with 4 different counters but still debugging as we speak.
I felt, I know some1 here been this situation b4 and made it work.
Bit shift is not available on 5/01 processor
 
'Bit shift' may not be available but MUL certainly is.

Reserve an 'N' register. (Let's use N7:10) If appropriate on machine start clear it.

When part to be rejected is detected then latch (OTL) bit zero. (OTL N7:10/0)

When the 'index' takes place one-shot that and use it to MUL N7:10 by 2.

The reject bit will be at N7:10/3. Use that address as a contact to energize the reject. Any other reject which happen will be in the lower bits following along.
 
I like Bernie's solution, but I'll offer another... ;)

Just roll your own shift register.
|  "BAD"     1-SHOT

|---] [---+---]/[---------------(LATCH)

|         |

|  LATCH  |

|---] [---+

|

| "INDEX"     ONS

|---] [-------]^[---------------(1-SHOT)

|

|  1-SHOT     B2                  B3

|---] [---+---] [---------------(SET)

          |

          |   B2                  B3

          +---]/[---------------(RST)

          |

          |   B1                  B2

          +---] [---------------(SET)

          |

          |   B1                  B2

          +---]/[---------------(RST)

          |

          |  LATCH                B1

          +---] [---------------(SET)

          |

          |  LATCH                B1

          +---]/[---------------(RST)

"BAD" is the input from the camera (although I would prefer a more 'fail-safe' method of monitoring a 'GOOD' signal from the camera, and use XIC instead).
"INDEX" is the signal from the machine that it has cycled.

Short description:

When a "BAD" signal is received, the "LATCH" bit turns on and stays on. The "INDEX" generates a one-shot. Each time it turns on:

1.) The current status of station 3 (B3) is updated with the status of station 2 (B2)
2.) The current status of station 2 (B2) is updated with the status of station 1 (B1)
3.) The current status of station 1 (B1) is updated with the current camera result ("LATCH")​

The "LATCH" bit is cleared on the following scan.

B3 contains the GOOD/BAD status (ON=BAD) of the part in station 3

🍻

-Eric
 

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