I am sending this sequence of commands in order to get waveform data:
':STOP'
':WAVeform:SOURce CHAN1'
':WAVeform:POINts 500'
':WAVeform:FORMat ASC'
xincrement = send_and_readline(':WAVeform:XINCrement?')
signal = send_and_readline(':WAVeform:DATA?')
but I am able to get 500 points only when both channels are on, when only channel 1 is on then I got always only 496 points, why?
Hi,
there is a note in the datasheet :
"If a full screen of data is not displayed, the number of points returned will not be 1000 or an
even divisor of it."
what does it exactly mean? Waveform must cover 100% of screen horizontally and vertically?
You can stop an acquisition before there are enough captured points to fill the screen horizontally. I think the note means "if you ask for 1000 points (or an even divisor of 1000 points) and a full (horizontal) screen of data is not captured, you're not going to get all the points you asked for".
I can't explain why you get only 496 points when you ask for 500 with one channel in the pair on. It probably has to do with decimation related to the time per division setting in Normal mode and then the additional decimation that occurs when asking for 500 points. There are also other factors that affect the maximum number of data points as described under "Length Control" in the user's guide.
Best Regards,
Pat
Hi Pat,
thanks for reply. i was playing with time division.it is looking that amount of samples you can get depend on it.
Hi Guys,
i have found that problem is when ACQuire:TYPE is Normal. When I have used Averaging then everything is ok.
Why there is a problem in Normal type?
Working example:
self.send_and_sync(":ACQuire:TYPE AVERage")
self.send_and_sync(":ACQuire:COMPlete 100")
self.send_and_sync(":ACQuire:COUNt 2")
self.send_and_sync(":DIGitize CHAN{}".format(channel))
self.send_and_sync(':WAVeform:SOURce CHAN{}'.format(channel))
self.send_and_sync(':WAVeform:POINts {}'.format(points))
self.send_and_sync(':WAVeform:FORMat ASC')
xincrement = self.send_and_readline(':WAVeform:XINCrement?')
signal = self.send_and_readline(':WAVeform:DATA?')