Experimental Physics and
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I have done something similar to what Bob suggests, in order to have a BI record (set to I/O Intr) trigger something else after a delay. With sysClkRateSet(2000) set in my st.cmd file, I was able to set delays with a resolution of 1msec. Jitter was surprisingly good, a few % of a msec, iirc. The setup was VxWorks / MVME5100, in a crate with lots of other stuff. The binary input was an IP-Unidig input. I experimented with higher clock rates but 2000 seemed to be the cutoff for high resolution coupled with reasonable jitter, on my setup. One thing I wanted to point out is that any old (in my case SNL) code using vxWorks taskDelays will be affected by this. Obviously your delays will get much shorter with a faster clock rate! I found this out the hard way. Another reason taskDelay() calls should be converted to epicsThreadSleep(). Kurt Goetze Dalesio, Leo wrote: If you have the OS tick rate at 1 K Hz, You could set the BO's HIGH field to something .001 - 1 millisecond set the SCAN rate to .01 Hz
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ANJ, 02 Sep 2010 |
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