How to zoom in on a waveform on oscilloscope ?
I'm using Yokogawa DL1540L Scope to measure watchdog timeout.
CH2 = 5V/div, CH4 = 5V/div, 50ms/div
Single shot, rising edge trigger set on CH2. CH2 is gpio port. In software I set this port to logic low right before I service the watchdog. In scope I see a positive spike, which is actually logic high and then after some short time, logic low. I want clear display that zooms this spike so it clearly show logic high and then logic low.
I tried to use buttons on scope to zoom but no luck.
If my time scale is set lower than 50ms/div, then I would see the pulse, logic high for short duration and then logic low. I can't see lower time scale because then I won't catch watchdog reset on CH4.
WatchdogTimeout.jpg
CH2 = 5V/div, CH4 = 5V/div, 50ms/div
Single shot, rising edge trigger set on CH2. CH2 is gpio port. In software I set this port to logic low right before I service the watchdog. In scope I see a positive spike, which is actually logic high and then after some short time, logic low. I want clear display that zooms this spike so it clearly show logic high and then logic low.
I tried to use buttons on scope to zoom but no luck.
If my time scale is set lower than 50ms/div, then I would see the pulse, logic high for short duration and then logic low. I can't see lower time scale because then I won't catch watchdog reset on CH4.
WatchdogTimeout.jpg
ASKER
It's a Digital Oscillope, Yokogawa DL1540DL. Attached is the user's manual.
I think when you say higher sweep speeds, you mean numbers less than 50ms/div. When I set sweep speed to 2ms/div, then I see narrow pulse on CH2 but then I don't see my reset pin going low. In order to see both waveforms, I need to be at 50ms/div because watchdog timeout is about 300ms.
The problem at 50ms/div is that pulses on both channels look like spikes because I'm at slow sweep speed.
Thank you for quick response over the weekend.
Yokogawa-DL1540L-scope.pdf
I think when you say higher sweep speeds, you mean numbers less than 50ms/div. When I set sweep speed to 2ms/div, then I see narrow pulse on CH2 but then I don't see my reset pin going low. In order to see both waveforms, I need to be at 50ms/div because watchdog timeout is about 300ms.
The problem at 50ms/div is that pulses on both channels look like spikes because I'm at slow sweep speed.
Thank you for quick response over the weekend.
Yokogawa-DL1540L-scope.pdf
ASKER CERTIFIED SOLUTION
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I also see that the manual was last printed in 1997 and that the scope has a Cathode Ray Tube. It may have some limitations compared to a modern Digital Storage Oscilloscope with an LCD screen and a high speed Analogue to Digital converter to bring in input signals and display them.
@naseeam - Did you try saving waveforms as suggested to collect what you want to see?
ASKER
I haven't have chance to read section 7 of the manual. Also, someone else has borrowed the scope. I will try your suggestion as soon as I can. I really appreciate the help.
Thank you. Please let us know when you have it back. Also read chapter 4 as there was good stuff in there on acquiring waveforms.
@naseeam - Thank you and I was happy to help. Good luck with your oscilloscope.
On my GW Instek 2304a or on my Tektronix 2024C (which are both digital storage oscilloscopes), I can use RUN instead of (say) Acquire to let the scope trace run once. Set it to store and then you can go back and review the trace.
You can sometimes use Delayed Sweep on an analogue scope to zoom in on segments of a trace but then I would normally use such a feature at much higher sweep speeds than 50 ms/div.
I think you need either a Digital Storage scope or a Logic Analyzer.