Goody
Member
Dear all
It is Sunday afternoon, I am tired (in fact exhausted) been programming solid for two days and the old brain is entering automatic shutdown.
My workload at the moment is just impossible. I have three plc projects on the go at once, and another seven awaiting urgent attention.
These are all design and build from scratch projects. It’s at the ‘I’m scared as to how I am going to cope’ level.
Now the problem I have at the moment is – how to get back from Manual operation to Automatic operation and continue the automatic operation from a set point.
Here is the problem in a nutshell;
I am using a Mitsubishi PLC and a HMI. The machine has two modes, Automatic and Manual.
I am using a sequencing method of programming the automatic part. (STL).
Mitsubishi sequencing works like this;
The whole ladder logic is scanned normally plus just the active step(s). The inactive steps are not scanned.
This allows double coiling (within limits) and nice easy programming of sequential blocks.
This machine is basically a ‘pick n place’ it cubes bricks for transporting away.
The bricks come down a conveyor; the grab picks up a row of bricks and places them on another conveyor, it then goes back and places another row of bricks on top of the last layer.
This goes on until a cube is made then the outgoing conveyor moves the cube down the line.
When a problem arises, i.e. the grab drops the bricks, something breaks etc. The machine is put into manual mode and the next layer is often done by hand, but not always, sometimes they need to start from exactly the same point in the sequence, sometimes further in the sequence.
They then want to put the machine back in automatic.
When the machine is put into manual, the STL part is reset and none of it is scanned. This is to avoid double coiling in manual mode (the same output may be needed in manual as well as the active step and this would cause conflicts within the program)
So, I need the correct step in the sequence to be activated when going back to auto.
The way I have done it is to have the HMI give the operator a choice on the screen of which part of the sequence to start in. i.e. PICK UP LAYER 7 or PLACE LAYER 5 etc. But, because of the size of the program (massive) and the many differing types of bricks. I have nearly 100 sequence steps. I cannot fit them all on one screen.
Other ideas I am toying with is, just give the operator 2 choices – pick or place. (simple is better)
I have an encoder on the grab up/down for accurate positioning and so could take a reading from the ‘place mode’ as to which layer it is on. (there is also a ‘back-off switch’ to tell the grab it has landed when placing)
But even so, if I use this last method, how do I then set the appropriate STL step. As you can tell from this ramble, the cognitive reasoning is overloaded; I am resting for a while to await inspiration,,,,,,,any suggestions would be appreciated.
It is Sunday afternoon, I am tired (in fact exhausted) been programming solid for two days and the old brain is entering automatic shutdown.
My workload at the moment is just impossible. I have three plc projects on the go at once, and another seven awaiting urgent attention.
These are all design and build from scratch projects. It’s at the ‘I’m scared as to how I am going to cope’ level.
Now the problem I have at the moment is – how to get back from Manual operation to Automatic operation and continue the automatic operation from a set point.
Here is the problem in a nutshell;
I am using a Mitsubishi PLC and a HMI. The machine has two modes, Automatic and Manual.
I am using a sequencing method of programming the automatic part. (STL).
Mitsubishi sequencing works like this;
The whole ladder logic is scanned normally plus just the active step(s). The inactive steps are not scanned.
This allows double coiling (within limits) and nice easy programming of sequential blocks.
This machine is basically a ‘pick n place’ it cubes bricks for transporting away.
The bricks come down a conveyor; the grab picks up a row of bricks and places them on another conveyor, it then goes back and places another row of bricks on top of the last layer.
This goes on until a cube is made then the outgoing conveyor moves the cube down the line.
When a problem arises, i.e. the grab drops the bricks, something breaks etc. The machine is put into manual mode and the next layer is often done by hand, but not always, sometimes they need to start from exactly the same point in the sequence, sometimes further in the sequence.
They then want to put the machine back in automatic.
When the machine is put into manual, the STL part is reset and none of it is scanned. This is to avoid double coiling in manual mode (the same output may be needed in manual as well as the active step and this would cause conflicts within the program)
So, I need the correct step in the sequence to be activated when going back to auto.
The way I have done it is to have the HMI give the operator a choice on the screen of which part of the sequence to start in. i.e. PICK UP LAYER 7 or PLACE LAYER 5 etc. But, because of the size of the program (massive) and the many differing types of bricks. I have nearly 100 sequence steps. I cannot fit them all on one screen.
Other ideas I am toying with is, just give the operator 2 choices – pick or place. (simple is better)
I have an encoder on the grab up/down for accurate positioning and so could take a reading from the ‘place mode’ as to which layer it is on. (there is also a ‘back-off switch’ to tell the grab it has landed when placing)
But even so, if I use this last method, how do I then set the appropriate STL step. As you can tell from this ramble, the cognitive reasoning is overloaded; I am resting for a while to await inspiration,,,,,,,any suggestions would be appreciated.