I have some problems for modelling the movement of a gantry. I hope you can help me. I have created two frames; (real system and approach1)
In the frame real_system, there are two sensors where the process is the next:
1.- A part arrives to sensor ID 1 and then waits a time X and the part goes to the Next sensor ID2.
2.- When the part arrives to the sensor ID2 the gantry takes it to the firts available machine.
3.- If a new part arrives to sensor ID1 the cycle is repeated (Wait a time X) and move to the sensor ID2
4.- The gantry takes the new part, verifies what machine will be first available and then replace the new part
5.- Finally the processed part is taken to the transporter and placed again on the ID2 sensor, where it waits a few seconds and is released.
Note: When the gantry is occupied sensor ID1 doesn't release the part until gantry is available.
In the frame approach1
I have tried to replace the sensors by two buffers to emulate the sensors functionality, but I can't program the correct code for the gantry takes the part and replace it to the first available machine.
I hope you can help me with your suggestions, This is the first time I'm modelling gantries
Thanks in advance
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attached is your model with this behavior implemented. It works by using a global variable to coordinate the sequence of MUs coming in, you could consider using this approach to solve your problem.
Thank you so much for your reply
Unfortunately the behaviour of the model is not as the real system.
Maybe I did not explain very well the process or not give you more details in fourth step:
When I said that the gantry takes the new part, I meant that takes a new mu from conveyor, then the gantry verifies again what machine is going to be available first, next carries the part to the machine, rotates the hook, replace the new mu and finally placed the already processed part on the conveyor.
I have attached an image to illustrate it
attached you will find your simulation model where the sensor controls are implemeted in a way to meet your requirements.
Hope this helps.
Thanks for your reply and your help.
Well I have one problem and a doubt:
1.- I replicated your model exactly with the same settings as you, but I get an error and really I don't understand what is wrong.
2. I replaced the Drain by a Buffer and I realized that conveyor1 does not accumulate more Mu's, why does it happen this behaviour?
I attached the two models so you can see the differences and the image with the error in GantryExample_Charly
just split off the waituntil:
waituntil target.occupied prio 1
waituntil part.finished prio 1
then it works
cont is a method and methods are typically not watchable; I guess internal there are exeptions for cont for Station and ParallelStation, but you try to move it from a Conveyor, so it doesnt work
freelance simulation specialist