PTO fundamentals

[Maninashed]

Hi All,

I have a few queries about the operation of the Vision PTO system. I've looked in the help files, pdf help files and online webinars but can't find the answers. Any help with the following would be gratefully received:

1.    My understanding of the "Units" and "Pulses" settings is that for example if you had a machine with a linear movement you wished to describe in millimtres and where 100 pulses from the PTO resulted in a movement of 1mm then the correct PTO Configuration settings would be Units = 1 and Pulses per Unit = 100. My question here is: would settings of Units = 2 and Pulses per unit = 200 produce the same results (1/100 being the same ratio as 2/200)?

2.    In PTO Set Profile settings, in what units are the values for Start/stop velocity and maximum velocity? I'm guessing pulses/sec, mm/sec (or whatever units have been set up in PTO Configuration) or perhaps something else?

3.    When executing PTO Set profile, what does status message 5 "Out of range" refer to?

4.    The help file section for PTO Set profile refers to 4 ranges of "minimum and maximum ranges for your motion profile". Are these ranges assigned automatically depending upon other parameters already defined or is there somewhere I haven't discovered where these need to be explicitly defined?

5.    When executing a PTO Move I've encountered a status message 5 "Currently in motion" despite the fact that I ensured that the previous movement had completed before starting another (by virtue of waiting for a status message 0 "Idle/OK" and Success bit = 1). Is there an explanation for this?

6.    Again when executing a PTO move I've encountered a move being prematurely terminated together with a non-zero staus message (can't clearly recall which one but I think possibly 1 "Configuration is invalid" or 4 "Absolute movement cannot be performed"). This suggests to me that some movement errors are only discovered mid-movement rather than before the movement starts. Is this correct?

Thanks in advance for any assistance.

[Maninashed]

And another peculiarity I've just encountered is:

7.    When executing a PTO move, the resulting Status output is sometimes 0 "Idle/OK" whilst the Success bit output is also 0. The help files show that the Success bit should be a 1 when the Status is 0. With some other implementations of the PTO move, I have achieved Status = 0 and Success = 1 as expected. Does the occurrence of 0 on both outputs indicate some other state that I haven't yet discovered?

[Joe Tauser]

Have you had a look at this? -

 

Joe T.

[Maninashed]

Hi Joe,

Thanks for the input. I did indeed see this in the last couple of days and also the version for its V350 friend. Whilst they were educational they didn't give any insight into the sort of problems I'm seeing.

I've just had a fairly intense and long day trying to make headway and I've arrived at a place where the PTO is mostly behaving itself in controlling 2 steppers, but only when set up with configuration and operating parameters which it decides are agreeable.

I'm coming to the conclusion that some combinations of configuration and operating parameters appear to produce error status messages from several of the PTO commands which are unexplained and unpredictable. I think that I'm simply unfortunate in that my application ideally wants to use problematic combinations so I'm having to make adjustments in my code to get to a robust place. I have a support ticket opened with Unitronics regarding what I'm discovering and I'll post the outcome and any further discoveries I make if it seems that it might be helpful to others.

In the meantime, it's still a mystery....... any further wisdom out there would be most welcome.

Thanks again.