Logging selected time-slices

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Ken Howell

Logging selected time-slices

Post by Ken Howell » Fri Apr 04, 2003 8:31 am


One of our research projects requires me to determine the torque on the shaft of a servo-motor over many (10,000) cycles. The rig will in fact have five of these assemblies, all the motors being cycled under the control of an OOPIC micr-controller.

I plan to make inferences as to the torque by measuring the servo load-current through a small resistor, and the derived voltage will be sampled through an ADC-11, and PICOLOG.

Each of the 10,000 cycles will last 60 seconds, though the actual servo operate duration per cycle will be only one second - hence, a duty cycle of 6:1 (ish) - there will of course be a return cycle within this period.

My problem is this: about 5/6ths of the time the system will be sitting ide, yet data will be being sampled, wasting space. I'm only interested in the one second per one minute cycle.

Is there some means by wich (perhaps via a signal on one of the spare channels) whereby I switch between pause and run?

Any ideas very much appreciated.


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Post by matthew » Fri Apr 04, 2003 8:46 am

Hi Ken,

Unfortunately, this is not something that PicoLog can do ... I like the idea though. I'm going to put this on as a wish list item for a future software version.
My initial thoughts on solving this in the short term are either to:
  • collect all of the data but then eliminate the non-useful data in a post processing operation, or
  • write an application which will only store useful data in the first place
Both of these are feasible, but the second will take longer to implement (although it is neater).

Best Regards,
Matt Everett

Pico Software Engineer

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