Basic Problem?

Fellow Members,

Processor SLC5/03, Redlion G307K2, Advantech Embeded PC for Cognex Camera Display. Bimba PFC with 120AC4-20mA

I have attached the program that I am having issues with. The problem is with Station 4. This station uses a Bimba Feedback cylinder to output 4-20ma which is scaled to turn on either a pass or fail bit.

The sequence for station 4 is as follows:
1. Part travels down conveyor and makes part in position LS
2. LS actuates part gate, which holds the part in place.
3. Part gate up LS and PArt gate output starts a settling timer. This allows the part to settle in place before actuating the measuring cylinder.
4. When the timer is complete it actuates the measuring cylinder output and extends the measuring cylinder.
4. The measurement is output and manipulated to determine if it acceptable or not.
5. The Pass or fail bit turns on and stays on. It isn't pulsed.

In theory when either the pass of fail bit comes on it releases both the measuring cylinder solenoid and the part gate. Thus releasing the part to travel down the conveyor to the reject station where it will be rejected once i write the Bit Shift Portion of the program.

I believe that my problem comes from the issue of having the pass or fail outputs on until the next cycle.

I am not just looking for someone to post an answer. I want to work thru the issue and understand why things are happening for each particular reason.

While I have been working with AB's since the 1776 and the BlueBox. I do not consider myself an expert by any means and have struggled with this particular problem for the last few days. Trying to work thru the issue myself. I am, however at a brick wall and I have a party coming to view the machine that is expecting to see it function.
Thank you in advance
View attachment Help.zip

cmarinello said:

I believe that my problem comes from the issue of having the pass or fail outputs on until the next cycle.

Click to expand...

Have you tried using a one-shot to test your theory?

Helliana,
Thank you for the reply.

I have not tried to use to use the OSR. I have no experience using it and have no idea where to begin. Sad to say.

This is often referred to as a racing condition. I would try the one shot to reset the station after you shift the bits.

Regards,

One thing I see- aren't you checking the part on rungs 9&10 before your settling timer is done? These rungs are being activated before your Bimba cylinder even begins to stroke?


You'll need a pause to settle and then another pause while the cylinder reaches full stroke.