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Home > Programming > Multiple Destacking Operations
rstuart

I am working on programming my cell. It consists of 4 load nests that allow me to stack 100 pieces in each stack. There is a prox switch at the bottom of each stack used for part present. I am trying to use the Seek/Destacking function to pick parts one by one. I load up all stations and press start. Robot unloads first station, no problem and starts unloading second. In the meantime, I place more parts in the first nest. The robot now returns to unloading the first nest before completely unloading the nest it was working on. I am using an If statement related to the part present sensors and calling a subprogram that has the destacking info in it. How can I get it to complete the stack it is working on without moving to another stack?
David_Gouffe

Hi, 

Your challenge is probably that at the beginning of the program you check the 4 stacks. This is checked, whenever you emptied a stack or not. 

This way, your program always start by checking : Is there a part on the first stack, process all of them, then check for stack 2, then stack 3 and then stack 4. 

The IO check should be done just at the beginning of the program when selecting the stack or after a single part is picked to see if the stack is emptied.

Here is the suggested approach for it: 

Create a variable assigned to 0 at beginning in the "before start" section.
"StackNb_Var:=0 "
To select the stack, use the actual "If" statement checking the IO of each stack.
This step is inside an "IF" statement only executing if the variable "StackNb_Var:=0 "

Inside each stack selected, assign the current stack corresponding to the IO signal.
"StackNb_Var:=3" 
(Here is the example of the stack 3, do the same for 1, 2 and 4)

The movements are associated with the current stack. You can select the stack with either a "IF" statement or a "Switch Case" structure. 

After each pick is done and the robot cleared the part up, then you can check if the Stack IO is OFF. A Stack IO off is stating the stack is done. 
The "IF" statement check the Stack_IO is equal to False and inside the IF statement, you set the variable "StackNb_Var:=0 " . This way the system will select the next stack to unload. 

N.B.:  "StackNb_Var"  is the variable name, whichever the name you choose.  

Hope this helps.

Regards, 
 

David_Gouffe

Hi, 

Your challenge is probably that at the beginning of the program you check the 4 stacks. This is checked, whenever you emptied a stack or not. 

This way, your program always start by checking : Is there a part on the firs stack, process all of them, then check for stack 2, then stack 3 and then stack 4. 

The IO check should be done just at the beginning of the program when selecting the stack or after a single part is picked to see if the stack is emptied.

Here is the suggested approach for it: 

Create a variable assigned to 0 at beginning in the "before start" section.
"StackNb_Var:=0 "
To select the stack, use the actual "If" statement checking the IO of each stack.
This step is inside an "IF" statement only executing if the variable "StackNb_Var:=0 "

Inside each stack selected, assign the current stack corresponding to the IO signal.
"StackNb_Var:=3" 
(Here is the example of the stack 3, do the same for 1, 2 and 4)

The movements are associated with the current stack. You can select the stack with either a "IF" statement or a "Switch Case" structure. 

After each pick is done and the robot cleared the part up, then you can check if the Stack IO is OFF. A Stack IO off is stating the stack is done. 
The "IF" statement check the Stack_IO is equal to False and inside the IF statement, you set the variable "StackNb_Var:=0 " . This way the system will select the next stack to unload. 

N.B.:  "StackNb_Var"  is the variable name, whichever the name you choose.  

Hope this helps.

Regards, 
 

David_Gouffe

https://dof.robotiq.com/discussion/1567/multiple-destacking-operations#latest


Hi, 

Your challenge is probably that at the beginning of the program you check the 4 stacks. This is checked, whenever you emptied a stack or not. 

This way, your program always start by checking : Is there a part on the firs stack, process all of them, then check for stack 2, then stack 3 and then stack 4. 

The IO check should be done just at the beginning of the program when selecting the stack or after a single part is picked to see if the stack is emptied.

Here is the suggested approach for it: 

Create a variable assigned to 0 at beginning in the "before start" section.
"StackNb_Var:=0 "
To select the stack, use the actual "If" statement checking the IO of each stack.
This step is inside an "IF" statement only executing if the variable "StackNb_Var:=0 "

Inside each stack selected, assign the current stack corresponding to the IO signal.
"StackNb_Var:=3" 
(Here is the example of the stack 3, do the same for 1, 2 and 4)

The movements are associated with the current stack. You can select the stack with either a "IF" statement or a "Switch Case" structure. 

After each pick is done and the robot cleared the part up, then you can check if the Stack IO is OFF. A Stack IO off is stating the stack is done. 
The "IF" statement check the Stack_IO is equal to False and inside the IF statement, you set the variable "StackNb_Var:=0 " . This way the system will select the next stack to unload. 

N.B.:  "StackNb_Var"  is the variable name, whichever the name you choose.  

Hope this helps.

Regards, 

David Gouffé

Integration Coach

Coach en intégration


Robotiq is now into packaging, palletizing and sanding applications. Learn more about our new Vacuum Grippers and the Robotiq Sanding Kit.


1-888-ROBOTIQ #275 (762-6847)

1-418-380-2788 #275 (Outside US and Canada)

1-418-655-9221 (Cell)

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David_Gouffe

Hi, 

Your challenge is probably that at the beginning of the program you check the 4 stacks. This is checked, whenever you emptied a stack or not. 

This way, your program always start by checking : Is there a part on the firs stack, process all of them, then check for stack 2, then stack 3 and then stack 4. 

The IO check should be done just at the beginning of the program when selecting the stack or after a single part is picked to see if the stack is emptied.

Here is the suggested approach for it: 

Create a variable assigned to 0 at beginning in the "before start" section.
"StackNb_Var:=0 "
To select the stack, use the actual "If" statement checking the IO of each stack.
This step is inside an "IF" statement only executing if the variable "StackNb_Var:=0 "

Inside each stack selected, assign the current stack corresponding to the IO signal.
"StackNb_Var:=3" 
(Here is the example of the stack 3, do the same for 1, 2 and 4)

The movements are associated with the current stack. You can select the stack with either a "IF" statement or a "Switch Case" structure. 

After each pick is done and the robot cleared the part up, then you can check if the Stack IO is OFF. A Stack IO off is stating the stack is done. 
The "IF" statement check the Stack_IO is equal to False and inside the IF statement, you set the variable "StackNb_Var:=0 " . This way the system will select the next stack to unload. 

N.B.:  "StackNb_Var"  is the variable name, whichever the name you choose.  

Hope this helps.

Regards, 
 

David_Gouffe

Hi, 

Your challenge is probably that at the beginning of the program you check the 4 stacks. This is checked, whenever you emptied a stack or not. 

This way, your program always start by checking : Is there a part on the firs stack, process all of them, then check for stack 2, then stack 3 and then stack 4. 

The IO check should be done just at the beginning of the program when selecting the stack or after a single part is picked to see if the stack is emptied.

Here is the suggested approach for it: 

Create a variable assigned to 0 at beginning in the "before start" section.
"StackNb_Var:=0 "
To select the stack, use the actual "If" statement checking the IO of each stack.
This step is inside an "IF" statement only executing if the variable "StackNb_Var:=0 "

Inside each stack selected, assign the current stack corresponding to the IO signal.
"StackNb_Var:=3" 
(Here is the example of the stack 3, do the same for 1, 2 and 4)

The movements are associated with the current stack. You can select the stack with either a "IF" statement or a "Switch Case" structure. 

After each pick is done and the robot cleared the part up, then you can check if the Stack IO is OFF. A Stack IO off is stating the stack is done. 
The "IF" statement check the Stack_IO is equal to False and inside the IF statement, you set the variable "StackNb_Var:=0 " . This way the system will select the next stack to unload. 

N.B.:  "StackNb_Var"  is the variable name, whichever the name you choose.  

Hope this helps.

Regards, 
 

David_Gouffe

https://dof.robotiq.com/discussion/1567/multiple-destacking-operations#latest


Hi, 

Your challenge is probably that at the beginning of the program you check the 4 stacks. This is checked, whenever you emptied a stack or not. 

This way, your program always start by checking : Is there a part on the firs stack, process all of them, then check for stack 2, then stack 3 and then stack 4. 

The IO check should be done just at the beginning of the program when selecting the stack or after a single part is picked to see if the stack is emptied.

Here is the suggested approach for it: 

Create a variable assigned to 0 at beginning in the "before start" section.
"StackNb_Var:=0 "
To select the stack, use the actual "If" statement checking the IO of each stack.
This step is inside an "IF" statement only executing if the variable "StackNb_Var:=0 "

Inside each stack selected, assign the current stack corresponding to the IO signal.
"StackNb_Var:=3" 
(Here is the example of the stack 3, do the same for 1, 2 and 4)

The movements are associated with the current stack. You can select the stack with either a "IF" statement or a "Switch Case" structure. 

After each pick is done and the robot cleared the part up, then you can check if the Stack IO is OFF. A Stack IO off is stating the stack is done. 
The "IF" statement check the Stack_IO is equal to False and inside the IF statement, you set the variable "StackNb_Var:=0 " . This way the system will select the next stack to unload. 

N.B.:  "StackNb_Var"  is the variable name, whichever the name you choose.  

Hope this helps.

Regards, 

David Gouffé

Integration Coach

Coach en intégration


Robotiq is now into packaging, palletizing and sanding applications. Learn more about our new Vacuum Grippers and the Robotiq Sanding Kit.


1-888-ROBOTIQ #275 (762-6847)

1-418-380-2788 #275 (Outside US and Canada)

1-418-655-9221 (Cell)

Follow us on

facbook-iconepng linkedin-iconepng twitter-iconepng google-iconepng Youtube-iconepng

Visit us:  
 

rstuart

I kind of lost track of this problem. I have managed to get the robot to pick all four stacks. The problem I am having now is once the fourth stack is empty and it returns to the first, the robot collides with the top of the stack. It is trying to reach the bottom of the stack rather than start
rstuart

So, I have sort of figure out what is going on, I think. When this program runs, it creates a position that can be seen in the variable screen on the teach pendant. They are labeled ur_start_position_51, ur_start_position_77, ur_start_position_103, and ur_start_position_129. The only time the robot does not collide when going to the stacks out of sequence is when these position have not been generated. Is there a way to clear or reset them in the program?