A little frustrated with the PropScope . . .

[FireNWater]

OK, I've been working thru the book for a couple days and have hit some issues. Hopefully they are something I've missed in the book, but I've re-read it a couple times and can't find mention. I'm pretty much self-taught as far as electronics goes, so my only resource is the BOE-bot and Propscope books. I bought a BOE to use with the P-scope.

1) When taking measurements, sometimes the Propscope will continue to run for a couple minutes while other times it just freezes after a couple seconds. I am currently on the "trim pot as voltage divider" exercise. The first time I ran it I could get the voltage to go up and down just fine, but now as soon as I hit "Run", the line moves either up or down a couple volts then the display freezes.

2) After spending an hour paging thru this forum I gather that when the time division is set to a low value the scope will only run for a few seconds - until its internal buffer fills up, then it transfers its contents to the computer thru the USB cable. Is the only way to take another measurement to cycle the "Run" button?

2.5) If I'm not in streaming mode, do I have to wait for the "connecting to COM 12" dialog boxes each and every time I want to take a new measurement? I know its only a few seconds, but after about 100 measurements it adds up.

3) Every time I try to select a longer time cycle, the software resets to 50us when I restart the scope. If I change the time cycle while it is running, will it change the Propscope's current run, or is it set to whatever was there when it started?

4) I have read in a couple posts that I need to remove the DAC card to use CH2. CH2 seemed to work fine on the earlier experiments and I was able to get results from the function generator after a few tries. Any guidance from Parallax here?

OK, that should hopefully get me rolling. . .

Thanks!!

[FireNWater]

Another question, is there an instruction manual other than the 350 page educational book? Don't get me wrong, I bought the Pscope for the book, but I can see there are times I'd rather just dig into a tech manual.

[Hanno]

Hi! Welcome to the forums and to PropScope.
Here is how the PropScope should work:
- the graph should continually update. If you've set a trigger, the graph will "freeze" until the trigger condition has been met, this may explain your issue
- when your timescale is set to a slow setting- like 1 sec/div then the samples will stream in continually and the graph will scroll from right to left
- when your timescale is set a faster setting- like 1 msec/div then the PropScope will collect 2 screens worth of data (taking 20 msec) and then display that
- you should not need to ever hit the "run" button. You can use it to pause updates and then resume, but you don't need to hit it to coax the PropScope to keep going
- PropScope should remember setting from one session to another on the same pc
- you can use Ch2 as long as you leave the function generator turned of. You can use either the function generator or Ch2.
Hanno

[FireNWater]

Hannover,

Thanks for the reply!!

How do I make sure I didn't accidentally set a trigger?

[FireNWater]

Hanno,

Here is a video of the Propscope while I was trying to do the voltage divider experiment.

http://www.youtube.com/watch?v=Ms7ZY9TKaSg

I was also running the I/O pin threshold test and it was working perfectly even after the Propscope display froze.

[FireNWater]

.
Just tried the Propscope with software version 2.0.3 on my main PC and got the same results, works great for a time, then freezes up. May be a defective unit?
.

[Hanno]

Hi,
On the "Oscilloscope" view in the bottom left there's a "Trigger" tab that let's you set the mode of the trigger, make sure this is set to "off". Thanks for the video, that's worth a thousand posts! I believe there's something faulty with your hardware setup possibly one of these:
- faulty USB cable, please try a different "standard" USB cable that's short, not-retractable, and shielded
- issues with USB system- try running on other PC, or reduce number of USB devices

I've just run v2.03 with your settings (50us, 2v) with varying input voltages on Ch1 for an hour with no problems.
It's possible that your PropScope hardware is faulty, but please check your USB first, and ideally try on a different PC.
Hanno

[FireNWater]

Hanno,

I am using the supplied USB cable. I did have the Homework Board plugged into the other USB port, but I'll try it by itself. I did try it on my desktop and got the same results.

Just went out and gave it one more try before packing it up. Now it just freezes after a couple minutes.

Are there any diagnostics I can run to determine where the problem is?

Also, I'm using Windows 7, 64-bit, on a Dell laptop.

Just tried an XP laptop, the software wouldn't even run on it . . . UGH!!

[Shawn Lowe]

Hanno,

I am using the supplied USB cable. I did have the Homework Board plugged into the other USB port, but I'll try it by itself. I did try it on my desktop and got the same results.

Just went out and gave it one more try before packing it up. Now it just freezes after a couple minutes.

Are there any diagnostics I can run to determine where the problem is?

Also, I'm using Windows 7, 64-bit, on a Dell laptop.

Just tried an XP laptop, the software wouldn't even run on it . . . UGH!!

I would contact parallax and exchange it for another, it sounds like a faulty unit to me

[Hanno]

I agree, sounds like the PropScope is faulty, please contact Parallax.
Hanno

[FireNWater]

Its on its way back to Digi-Key.

[Tom C]

@FireNWater,
Did you ever get your PropScope repaired?
Regards,
TCIII