load steps

[lucavilla]

Good Morning everyone!

I wanted to ask advice about a programming problem.

I'm working on a rotating bending test machine and my aim would be to manage the load step.

I want to create different commands to set at the beginning of the trial to manage the speed and the desired voltage for each load step.

an idea of what I want to do is in the attached image.

any suggestions?

thanks in advance.

Villa Luca

[0utlaw]

Hello Villa,

From your first post it's not very clear what you are trying to do- it looks like you need to send a variable analog output at set intervals, but what are you attempting to control?  Do you already have hardware?  What model/part number is it? Do you need to send an analog signal or a command/message of some sort to the test machine? How fast are the transitions between steps?  How long does each step last? What are the "low" periods between steps?

Regards,

[lucavilla]

Thanks for your answer I'll try to be more clear.

I have a DAQ NI USB-6008 and I can now control the machine, but only with the same step.

I have to send analog input to the pressure so that I can change the load on the mandrel.

But now I want my steps are no longer the same, but are random in the way that I determine to start of program.

for example:

1st step: 10000 turns of the mandrel at 100MPa

2nd step: 5000 turns at 250MPa ecc

I have already all the material to take the stress of the proof, the number of turns of the mandrel etc.

I want to create another program to make the steps random.

any suggestion?

thanks in advance.

Luca Villa

[pjr1121]

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@lucavilla wrote:

But now I want my steps are no longer the same, but are random in the way that I determine to start of program.

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Something can't be random and pre-determined at the same time.  If you indeed have a known sequence you wish to load at the start of the program, this can be read in from a file (.txt, .csv, or .ini) as a 2D array (# turns and Pressure for each step in sequence) or simply stored as an array constant if it isn't ever going to chagne.  

If, however, you truly wish for it to be random, these values must be calulated at run time based on existing physical limits; max/min values, & round up to acceptable values.  Say your pressure control is only accurate to 10 MPa, then sending 250MPa and 253 MPa are essentially the same thing.  You also need to consider how many steps to run in the sequence.  Are you going to limit the system by a number of steps or by the total time it runs, or a total number of "turns"?