How to trigger Siglent SDS1000X-E series scope correctly

Thread Starter

GregJ7

Joined Jun 7, 2014
42
I am a brand new oscilloscope user with a Siglent SDS1104X-E. There's a lot I have to learn about this device, but I thought some things would be simple, but apparently I am more clueless than I anticipated. I press Default to reset the scope to factory settings, then attach the GND of probe 1 to the negative terminal of a 4.1V battery (multimeter verifies the voltage), and make sure I would see the graph of the line (2V/div). I select triggering mode Single (after which the 0V horizontal graph line disappears), then touch the probe to the positive end of the battery. I am expecting to see a 4.1V flat line appear and may or may not perceive that the graph is not updating any further. However, nothing at all happens. The default settings for triggering look right (rising edge, DC coupled, tried trigger voltages around 40-120 mV, etc.) Anyone familiar with this line of scopes? Any idea what the problem might be?
 
You have to set the trigger level, the knob on the lower right. Set the trigger to positive edge detect and rotate the knob slightly clockwise. You will probably see a small symbol along one edge of the display to indicate the actual level. Then touch the probe to the battery.
 

Yaakov

Joined Jan 27, 2019
1,547
You have to set the trigger level, the knob on the lower right. Set the trigger to positive edge detect and rotate the knob slightly clockwise. You will probably see a small symbol along one edge of the display to indicate the actual level. Then touch the probe to the battery.
He's done that, according to his description. I think he's just triggering too early and sweeping too fast to see what he expects.
 
He's done that, according to his description. I think he's just triggering too early and sweeping too fast to see what he expects.
He is looking at a DC level with single sweep, no such thing as triggering too early. If the trigger occurred prior to touching the battery terminal he would still see a flat line at 0 volts.
 
The oscilloscope really is an instrument that measures time varying signals. Since a battery is not time varying, you need to use Auto-trigger which essentially means the scope gets triggered in the absence of a trigger condition.

Auto-trigger on a sine wave can result in the waveform traveling across the horizontal. Normal trigger allows you to select a level and slope to start the sweep. You can generally set the trigger source too. Internal (channel), external, line (power line) are popular.

Seeing a fellow classmate set up a dual time base delayed sweep oscilloscope can be a daunting task. e.g. the Tektronix 465B
 

Yaakov

Joined Jan 27, 2019
1,547
The oscilloscope really is an instrument that measures time varying signals. Since a battery is not time varying, you need to use Auto-trigger which essentially means the scope gets triggered in the absence of a trigger condition.

Auto-trigger on a sine wave can result in the waveform traveling across the horizontal. Normal trigger allows you to select a level and slope to start the sweep. You can generally set the trigger source too. Internal (channel), external, line (power line) are popular.

Seeing a fellow classmate set up a dual time base delayed sweep oscilloscope can be a daunting task. e.g. the Tektronix 465B
The single trigger mode can easily show you the rise time from connecting the battery but if it the trigger level is very low and the sweep very fast the waveform will appear flat. I can reproduce this here, and with a higher trigger level and a relatively slow sweep I can get a wave form to display.
 

Yaakov

Joined Jan 27, 2019
1,547
He is looking at a DC level with single sweep, no such thing as triggering too early. If the trigger occurred prior to touching the battery terminal he would still see a flat line at 0 volts.
Noise can trigger the scope, it does for me at those levels, the waveform seen is a flat line at 0V.

That's why i suggested the trigger be increased and the sweep reduced.
 

Thread Starter

GregJ7

Joined Jun 7, 2014
42
Thanks all for answering. It turns out that my scope wouldn't trigger while the trigger voltage was 240 mV or less. At 280 mV it works. The default sweep is fine (1 µs) Btw, the graph (after adjusting horizontal div) shows that it takes 1 µs for voltage output to rise (on a curve) from 0 to my battery voltage. This could be a delay due to scope internals for all I know, though. Don't know much about batteries. Maybe chemical reactions need to start for current to flow.
 
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Try this, you have a calibration point on the bottom center of the front panel. This should be a 1 volt p-p signal at 1KHz. Attach your probe to it with the vertical resolution set to 200mV/div, trigger to auto. Make sure the trigger source is set the the channel you are using. Adjust the horizontal to show a few cycles.
Try adjusting the trigger level up and down. When the level is within the range of the signal the trace should become stable. Switch the sweep mode to normal and try adjusting the trigger again. The trace will be visible when the trigger level is set properly and you will not have a trace with the trigger level out of range.
 

Yaakov

Joined Jan 27, 2019
1,547
Thanks all for answering. It turns out that my scope wouldn't trigger while the trigger voltage was 240 mV or less. At 280 mV it works. The default sweep is fine (1 µs) Btw, the graph (after adjusting horizontal div) shows that it takes 1 µs for voltage output to rise (on a curve) from 0 to my battery voltage. This could be a delay due to scope internals for all I know, though. Don't know much about batteries. Maybe chemical reactions need to start for current to flow.
I set up a test using a bench supply and a momentary switch for more consistency. I find the triggering on falling (opening the switch) is much more reliable and selecting a good sweep time gives much more information.

upload_2019-5-21_10-18-26.png
 

Thread Starter

GregJ7

Joined Jun 7, 2014
42
Try this, you have a calibration point on the bottom center of the front panel. This should be a 1 volt p-p signal at 1KHz. Attach your probe to it with the vertical resolution set to 200mV/div, trigger to auto. Make sure the trigger source is set the the channel you are using. Adjust the horizontal to show a few cycles.
Try adjusting the trigger level up and down. When the level is within the range of the signal the trace should become stable. Switch the sweep mode to normal and try adjusting the trigger again. The trace will be visible when the trigger level is set properly and you will not have a trace with the trigger level out of range.
Thanks, Charles. It would have taken me a while to figure out that the scope trigger sensitivity was tied to my vertical div setting, but it is and your suggestion works. I do note now, however, that the trigger increments are dependent on the vertical div setting, as well, and this behavior probably shows up with other features of the scope, too.
 
Since the input attenuator scales the input, the trigger is actually referenced to the visible screen.

Another feature you need to be aware of is the ability to shift the trigger horizontally. If you look at the image in Yaakovs last post you will see a small blue inverted triangle at the top of the screen. I'm not exactly sure how to control it, probably the controls in the upper left of the scope. Moving the triangle to the right allows you to look at pretrigger information. This is a nice feature of digital scope that we didn't have with the old analog scopes.

Enjoy learning how to use the oscope.
 

Yaakov

Joined Jan 27, 2019
1,547
Since the input attenuator scales the input, the trigger is actually referenced to the visible screen.

Another feature you need to be aware of is the ability to shift the trigger horizontally. If you look at the image in Yaakovs last post you will see a small blue inverted triangle at the top of the screen. I'm not exactly sure how to control it, probably the controls in the upper left of the scope. Moving the triangle to the right allows you to look at pretrigger information. This is a nice feature of digital scope that we didn't have with the old analog scopes.

Enjoy learning how to use the oscope.
The horizontal position knob moves it. Here is it set to -200μs, denoted as "Delay" at the top.

upload_2019-5-22_6-2-3.png
 
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