USB function generators?
in [Design]
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From: Martin Riddle on 7 May 2010 21:32 "Joerg" <invalid(a)invalid.invalid> wrote in message news:84jn57FdkjU1(a)mid.individual.net... > Martin Riddle wrote: >> "Joerg" <invalid(a)invalid.invalid> wrote in message >> news:84jlc9F5giU1(a)mid.individual.net... >>> Nico Coesel wrote: >>>> Joerg <invalid(a)invalid.invalid> wrote: >>>> >>>>> Gents, >>>>> >>>>> Unless it rains on Sunday and I have some time I might just junk >>>>> this dreaded Wavetek Model 23 generator. Looked around for >>>>> USB-based generators and found a nice li'l scope/gen combo: >>>>> >>>>> http://www.allspectrum.com/store/product_info.php?products_id=2778 >>>>> >>>>> Not a lot of info, seems it has no galvanic isolation from the >>>>> computer like some others <knuckles turning white ...>. However, >>>>> unlike many others it does go down to 5 millihertz so can be used >>>>> in machine, stress and vibration testing which I need to do at >>>>> times. >>>>> >>>>> What do thee think? >>>> USB isolators are probably not expensive. >>>> >>> In this case it would be a bit more challenging because the thing is >>> also supplied via the USB jack. I could fix that, but ideally I'd >>> like something I can plug in and it just works. >>> >> >> We bought a few of the Keterex boxes. They work well. >> <http://www.mouser.com/ProductDetail/Keterex/KXUSB-150/?qs=%2fRwqiB95gejWb5h7F1VyFQ%3d%3d> >> > > That could work, if it's happy with 400mA. Unfortunately a lot of > stuff these days exceeds even the max load of 500mA, in particular > disk drives. > I couldn�t say if it actually sources 400ma since our USB devices have their own power source. On another note, My laptop's USB port cannot supply power to 2 2.5" drives at once, nasty head movement occurs. Cheers
From: Joerg on 7 May 2010 21:36 Martin Riddle wrote: > "Joerg" <invalid(a)invalid.invalid> wrote in message > news:84jn57FdkjU1(a)mid.individual.net... >> Martin Riddle wrote: >>> "Joerg" <invalid(a)invalid.invalid> wrote in message >>> news:84jlc9F5giU1(a)mid.individual.net... >>>> Nico Coesel wrote: >>>>> Joerg <invalid(a)invalid.invalid> wrote: >>>>> >>>>>> Gents, >>>>>> >>>>>> Unless it rains on Sunday and I have some time I might just junk >>>>>> this dreaded Wavetek Model 23 generator. Looked around for >>>>>> USB-based generators and found a nice li'l scope/gen combo: >>>>>> >>>>>> http://www.allspectrum.com/store/product_info.php?products_id=2778 >>>>>> >>>>>> Not a lot of info, seems it has no galvanic isolation from the >>>>>> computer like some others <knuckles turning white ...>. However, >>>>>> unlike many others it does go down to 5 millihertz so can be used >>>>>> in machine, stress and vibration testing which I need to do at >>>>>> times. >>>>>> >>>>>> What do thee think? >>>>> USB isolators are probably not expensive. >>>>> >>>> In this case it would be a bit more challenging because the thing is >>>> also supplied via the USB jack. I could fix that, but ideally I'd >>>> like something I can plug in and it just works. >>>> >>> We bought a few of the Keterex boxes. They work well. >>> <http://www.mouser.com/ProductDetail/Keterex/KXUSB-150/?qs=%2fRwqiB95gejWb5h7F1VyFQ%3d%3d> >>> >> That could work, if it's happy with 400mA. Unfortunately a lot of >> stuff these days exceeds even the max load of 500mA, in particular >> disk drives. >> > > I couldn�t say if it actually sources 400ma since our USB devices have > their own power source. > I think that's what the Keterex datasheet says. > On another note, My laptop's USB port cannot supply power to 2 2.5" > drives at once, nasty head movement occurs. > Well, that's the other problem. I've usually already got some lab stuff hanging on the laptop and while this is a ruggedized computer there will be a limit. The Velleman datasheet isn't exactly forthcoming with data like that. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joe G (Home) on 7 May 2010 21:37 Analog devices have a USB isolator IC, but you still need power isolation. Joe
From: Martin Riddle on 8 May 2010 15:45 "Joe G (Home)" <joe.g(a)optusnet.com.au> wrote in message news:4be4c068$0$22779$afc38c87(a)news.optusnet.com.au... > Analog devices have a USB isolator IC, but you still need power > isolation. > > Joe > That�s what is in the Keterex box. Cheers
From: miso on 8 May 2010 18:38
On May 7, 2:13 pm, Joerg <inva...(a)invalid.invalid> wrote: > Gents, > > Unless it rains on Sunday and I have some time I might just junk this > dreaded Wavetek Model 23 generator. Looked around for USB-based > generators and found a nice li'l scope/gen combo: > > http://www.allspectrum.com/store/product_info.php?products_id=2778 > > Not a lot of info, seems it has no galvanic isolation from the computer > like some others <knuckles turning white ...>. However, unlike many > others it does go down to 5 millihertz so can be used in machine, stress > and vibration testing which I need to do at times. > > What do thee think? > > -- > Regards, Joerg > > http://www.analogconsultants.com/ > > "gmail" domain blocked because of excessive spam. > Use another domain or send PM. USB is always a driver hassle. I try to buy USB devices that also work in Linux, so if the company goes bust, you can at least run the box under linux. $300 would get you a nice function generator at a ham swap meet. My PM5191 was $125 in a freakin' store (RA Surplus, now defunct) years ago. You can't get much money for low bandwidth generators these days. |