Debug: Ladder Logic

Hello,

I'm just starting to learn PLC, and need some help with debugging the attached ladder logic. I can't seem to figure it out. Any help will be great appreciated! I'm really want to learn.

https://imgur.com/a/BLpMkbB

Thank you!

Some suggestions:
1) post a legible version of the code; PDF is probably the best option (Select the [Print...] option, then choose [Microsoft Print to PDF] as the printer device, then attach the PDF here).

2) State what you want the code to do, and what you actually told it to do instead; point to a specific rung, or rungs, if possible

I have attached a better resolution photo through Imgur and will try to upload a pdf as well.
https://imgur.com/a/BLpMkbB

See video of the equipment here. 0:11 to 0:28.
https://www.youtube.com/watch?v=xqKIqNUufSI

The system inputs are:
X0 = Cycle Start Button
X1 = Cycle Stop Button
X2 = Emergency Stop Button
X3 = Feedback from conveyor system. Drive is on
X4 = Fill nozzle gantry is in Fill position
X5 = Fill nozzle gantry is in Retract position
X6 = Volumetric dispenser is running
X7 = Volumetric dispenser has completed cycle
X8 = Bottle shuttle in entrance position
X9 = Bottle shuttle is in exit position
X10 = Sensor to detect fourth bottle in fill shuttle
X11 = Sensor to detect eighth bottle in fill shuttle
X12 = Sensor to detect first bottle in fill shuttle
X13 = Shutter open to allow bottles into shuttle
The system outputs are:
Y0 = Conveyor drives run forward
Y1 = Pneumatic valve to raise fill nozzle gantry
Y2 = Pneumatic valve to lower fill nozzle gantry
Y3 = Start dispense cycle
Y4 = Stop dispense cycle
Y5 = Pneumatic valve to move bottle shuttle to exit position
Y6 = Pneumatic valve to move bottle shuttle to entrance position
Y7 = Pneumatic valve to open shutter to allow empty bottles into shuttle (3/2 valve, shutter automatically closes when output is turned off)

Production operators are reporting a number of bugs with this machine. Here is a partial list:
1. Conveyor stops when the Cycle Stop button is pressed, but conveyor continues to run when Emergency Stop is pressed, causing a safety hazard.
2. Bottle shuttle starts to move before fill nozzles are completely outside of the bottle, causing a crash.
3. Dispense starts before the gantry is at the fill position, causing liquid to miss the bottle.
4. If the bottles bind up and don’t fully fill up the shuttle, the fill routine starts anyway, causing a crash between the nozzles and misplaced bottles.
5. The shuttle often returns with one full bottle instead of waiting until all 8 bottles have left on the exit conveyor, causing a bottle to be double filled.

I hope this helps and thank you for the quick reply.

To help you to decipher the program listing, I would suggest you pencil in a description for each of the X inputs and Y outputs. The first rungs are inputs transferred to C "bits, so then make a relevant description for each. If you know how the machine works, the logic should start to make sense. Then think of conditions and sensors that may need to be added or revised.

Technology said:

3. Dispense starts before the gantry is at the fill position, causing liquid to miss the bottle.

Click to expand...

[X4/C4 = Fill nozzle gantry is in Fill position] is never tested in a NO or NC contact.

Rung 31 Needs to have XIO(X3) in series to perform estop operation.

Although I would recommend switching to a rated Safety Estop circuit, which interrupts the flow of power to the conveyor using Safety Relays, or if it's a safety PLC then performs a safety stop using any safety protocol like CIPSafet, ProfiSafe etc. Not sure what coding environment this is, but is it a homework question?

Looks a lot like Automation Direct, perhaps Click.

Technology said:

1. Conveyor stops when the Cycle Stop button is pressed, but conveyor continues to run when Emergency Stop is pressed, causing a safety hazard.

Click to expand...

If the E-stop button doesn't not work, stop what you are doing right now, and go turn off the disconnect and hang your padlock on it.

The E-stop must be hardwired, tested, and proven to work to the level of reliability required by a hazard analysis.

jaden said:

Looks a lot like Automation Direct, perhaps Click.

Click to expand...

It's a Do-More by Automation Direct.