Timing in RT
- From: Snamprogetti <x@xxxxxxxx>
- Date: Mon, 11 Sep 2006 07:10:08 -0500 (CDT)
I noticed some weird behavior about synchronism in a RT program of mine, so i did a test: i ran a simple VI with a 1 second timed loop, which just writes current time (including milliseconds) on a file. Everything's ok on PC, but on RT the written times don't match exactly with clock seconds, i got results like this:
14:00:37.124 14:00:38.120 14:00:39.118 14:00:40.113 14:00:41.111 14:00:42.107 ...
Cycles are shorter by a few milliseconds, compared to system time. This was with a Timed Loop structure; by using a While loop with "Wait until next multiple" i get the opposite!
14:05:28.717 14:05:29.718 14:05:30.719 14:05:31.720 14:05:32.721 14:05:33.721 ...
If i set the FP to use a Time Server, it's same thing but there are periodic "jumps", probably caused by the Time Server adjusting the clock:
... 13:42:31.979 13:42:32.974 13:42:33.971 13:42:34.968 13:42:36.112 13:42:37.109 13:42:38.106 13:42:39.102 ...
Looks like, in RT, system timer and timers used by VIs are not aligned. Do you know any info about the matter, and how to align them?
.
- Prev by Date: Re: cannot create a simulated device
- Next by Date: Re: while loop does not stop
- Previous by thread: Re: cannot create a simulated device
- Next by thread: save spreadsheet data to every row
- Index(es):
Relevant Pages
|
