Hello all,

I'm working on inspection system for labeling machine .

I used Cognex 7600  vision camera and PLC_CPU 1212 .

the camera inspect the quality of the printed info on the  bottle's  and get bass and fail .

Based on the camera result, the rejection system will pass good bottle's and reject bad ones.

1. What is the cycle time of the PLC? (150 ms)
   
   
2. What is the pulse speed of the encoder? (1000 pulse/sec)
   
   
3. How far is the inspection system from the reject? 400mm 
4. What is the maximum number of bottles which be busy travelling between the inspection system and the reject?    8
   
   
5. To which PLC input is the inspection system's signal connected to?I0.4 , I0.5

i used shift register  in my code as shown in pic , but the problem that the bottles not do not move regularly and continuously behind each other. One bottle may pass, and after a short period of time another pass. The distances between the bottles are irregular and unstable.

Therefore, when using a Position Sensor to make shifting, the process did not succeed, because the conveyor continues to move, and one bottle may pass and remain at bit number 7 Without shifting it to bit number 0 (  the rejector make action when bit #0 is 1 and the rejection sensor is 1)

any body know what to do in this case or if there's any example for similar project ?

Regards.

My comments in your original topic (Use shift register) still applies. You still need to know how many encoder pulses go into 1mm of distance.

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In summary the design you need is as follows:

1. The position of the encoder is captured as the object leaves the inspection system.
   
   
2. A calculation is made of what the encoder position would be when the object reaches the reject.
   
   
3. The future position is stored in a list (array). The list is managed with a FIFO concept which is the equivalent of a shift register.
   
   
4. An object has reached the reject when the oldest "future" value is less than the encoder's current position.

Have a look at the following posts:

Monitoring multiple positions with a single encoder

Encoder Counts Distance

S7-1200 HSC Rollover