Need some clarifications for this new beastie

Products & Technology DSO Quad
#1

I’m doing some work with analog synthesis, and needed a scope. Didn’t have space for an old/refurb Tek model, and didn’t have $$ for some of the higher end small units that connect to my system… The DSO Quad looked like a good choice.

I don’t think my use is going to get into the problems noted about analog bandwidth; I’m strictly going to be in the audio frequency range and below, no intent to use it for debugging high speed digital stuff.

But I do have some questions from other things I’ve read. The community Wiki talks about the voltage limit being 10Vpp, but other sites and the official docs say 80Vpp. Since I’m working with a +/- 15V supply I could easily get 30Vpp when measuring things, and I want to confirm that the higher value is correct and I’m not going to be risking frying something every time I use it with the 1x probes.

My other concern has to do with the dire warnings such as “never connect your DSO to OSX”…well, since my first step was to charge the thing, and my primary system is a macbook pro…I’ve already connected it to OSX. HOWEVER, I do not see the device as a USB drive on my system, which makes me think that the dire warnings are ONLY for going into bootloader/firmware loading mode. I do have boot camp and an Open Solaris server (which would very likely work just like Linux has been documented, even though it’s not supported).

But I wanted to confirm that as well…

So to summarize:

What is the actual Vpp limit on this device using the 1x probes?
Do the OSX warnings only apply for firmware loading mode?

Thanks…

EDIT: i suppose I should note that when I boot, firmware is listed as 2.6.0, SYS as 1.51, and APP as 2.52.

#2

I think the 10Vpp in the wiki means 10V/div, because that is the highest range selectable in the GUI. In this range, it is able to measure up to ±50 volts.

Studying the schematic, the input protection seems to be based on the clamp diodes of OPA2354. They are specified for 10mA current, and the series resistance at input is about 1Mohm - therefore the diodes themselves would be ok for up to 10kV. Another factor is the CPC1017 optocoupler, which is specified for 60V load voltage - but not all of the input voltage goes over the optocoupler, so it shouldn’t be a problem either.

The limiting factor is probably the PCB design - judging by the eye, it has about 0.2mm isolation, which may spark through at some 100V.

So, keeping in mind that I don’t work for seeed so I cannot say anything official, I would say that 30Vpp is definitely safe.

Regarding the OSX issue, I haven’t heard about it but OSX does write some random files to USB discs so it may be a problem. As long as you don’t boot into bootloader, the worst thing that can happen is that the filesystem on the disc may get corrupted which stops you from saving files. Then you need just to format it under Windows to restore it.

BTW. if the device is turned off, you can charge it but it won’t show up over USB.

#3

Thank you. That’s an “aha” moment–you’re right I didn’t connect it while powered on. I’m thinking I’ll just avoid doing that then.

I appreciate the reassurance even if you’re not an official spokesperson. :slight_smile:

#4

I’ve applied 37V DC on mine with both 1:1 1:10 probes.
It works just fine.

Can’t comment on the O/S thing however.