Rigol DS4024 Scope:Does Trace Persistance Work The Same On Other Scopes? - Page 1
Forum section: electronics / projects

author: martys
author_rank: Regular Contributor
timestamp: July 21, 2017, 09:03:15 pm
content: f I am using my DS4000 series scope to view a periodic pulse in Normal trigger mode, shouldn't the Persistence Time setting to "min" cause the display to clear the display after a few milliseconds?Setup:No Acquire or Single Sweep function used.Normal triggering, edge, level is set to properly trigger withing the amplitude window of the expected pulse.The Normal trigger functions correctly, every time a slow rep rate pulse occurs, it correctly triggers a new sweep.Trace Persistence is set to "min" (Trace Persistence can be set over a large range from "min" to "infinity" duration.)Time/Div: 1-mSec/DivDelayed Sweep OffThe problem is that the most recent pulse that triggered a sweep remains forever displayed, showing no regard to Trace Persistence settings.If I am monitoring a pulse from a Human or from a device, I must know, at a glance, when the pulses have stopped occurring, and while high pulse repetition rates will display thousands of overlapping pulses, depending on Trace Persistence settings.However in Normal Mode, the scope fails to blank a stale display, even when no storage function is activated.Using Auto triggering is often useless, the pulse jumps all over the display length and sometimes cannot be seen at all.Roll mode allows pulses to be seen, but only as thin vertical line blips and doesn't show the details (shape,width) correctly.On a conventional analog oscilloscope, the persistence of a triggered display is strictly controlled by the phosphor itself, on older storage scope, the trace is remembered and kept displayed until cleared, but on this digital scope, one doesn't know at a glance if the pulse train has ceased.On this Rigol scope, there are many Trace Persistence settings from "min" to "infinite" to choose from, why can't they be used while in Normal trigger mode?How could this be normal operation?Would an Agilent or Tek scope behave the same?

author: 2N3055
author_rank: Super Contributor
timestamp: July 21, 2017, 10:51:10 pm
content: In NORMAL mode people don't post same question twice ...It is not Rigol... It is you. Read the manual. AND yes it's not only Rigol, EVERY digital scope behaves like that.What you think is normal is called AUTO. It will trigger on a signal if there is trigger, if for some time there is no trigger, it times out and forces a trigger..So if there is a signal, it will show you, if signal disappears, in a second it will erase screen and show you flatline .NORMAL means it will trigger on a trigger event, show a capture on the screen, and than wait for another trigger event. In meantime it will show last capture.In upper left corner you have mark that shows STOP, WAIT, T'D and SINGLE... If scope is continuously triggering ( therefore showing fresh data ) you will see T'D flashing up there.. If it shows STOP, or WAIT you are looking at old data from last trigger...What you have is actually really nice scope, and quite complicated... You need to read the manual really thoroughly, and learn many things...Have fun!!

author: martys
author_rank: Regular Contributor
timestamp: July 21, 2017, 11:59:12 pm
content: 2N3055, your reply seems a bit troll-like with its use of condescension, pejorative judgement, and presumption about my level of experience with electronic equipment and realizing the need to read user manuals.In addition to your list of triggering notifications in the top left corner of the screen, you have omitted "RDY".I am aware that there are differences between operation of various brands of oscilloscopes and some brands have bugs and shortcomings and personality.It is foolish to say that "all scopes work that way", you obviously haven't experienced the use of all digital scopes available.This Rigol scope DS4000 series seems to have a few triggering gotches, especially obvious when using the longest sweep times.I had read the Rigol DS4024 User Guide Mar 2014 carefully (Section 12.3) before posting and it says almost nothing about Trace Persistence except how to set it(which is self-explanatory..you twist the knob or push the button), beyond showing only one example how Trace Persistence settings affect the write-over of older traces when the scope is used in the discrete case of viewing a very repetitive waveform such as a sinewave.The User Manual fails to clarify how Trace Persistence behaves using different trigger modes and is in fact, extremely short in explanation, so fails to disambiguate the details of Trace Persistence setting behavior using Normal triggering.I am eager to for someone to compare the operation of Rigol DS4000 series scopes with Tek or Agilent using Normal triggering and Trace Persistence.I think it is normal to post twice the same question(but in different forum areas of discussion) when I don't get the replies that answer my postings in one venue and the topic seemingly has failed to get viewing attention of those online and after a considerably long wait for replies.

author: nugglix
author_rank: Regular Contributor
timestamp: July 22, 2017, 06:54:35 am
content: What you think is wrong.Here double posts are not welcome.Same for calling out others as trolls because they just gave an answer you didn't like.I bet you're on the way to lots of ignore lists...

author: Simon
author_rank: Unknown
timestamp: July 22, 2017, 07:34:46 am
content: Please don't double post. It is extremely annoying to users trying to help you and displays large amounts of disrespect to them giving up their time to help.