USB function generators?
in [Design]
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From: Nico Coesel on 8 May 2010 19:16 "miso(a)sushi.com" <miso(a)sushi.com> wrote: >On May 7, 2:13=A0pm, 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=3D2778 >> >> 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. Well... a good HP3314A still sells for a couple of hundred. More recent Agilent generators fetch even more. AFAIK those are USB and/or ethernet controllable. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico(a)nctdevpuntnl (punt=.) --------------------------------------------------------------
From: Nico Coesel on 8 May 2010 19:46 Joerg <invalid(a)invalid.invalid> wrote: >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. If its from Velleman I'd stay away from it. They also sell kits. You can download the schematics from their website. The designs are far from brilliant and kits that are intended to be connected to the mains only meet the PCB design rules minimum clearance. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico(a)nctdevpuntnl (punt=.) --------------------------------------------------------------
From: Joerg on 8 May 2010 19:58 Nico Coesel wrote: > Joerg <invalid(a)invalid.invalid> wrote: > >> 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. > > If its from Velleman I'd stay away from it. They also sell kits. You > can download the schematics from their website. The designs are far > from brilliant and kits that are intended to be connected to the mains > only meet the PCB design rules minimum clearance. > Yes, it is from Velleman. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: miso on 8 May 2010 21:09 On May 8, 4:16 pm, n...(a)puntnl.niks (Nico Coesel) wrote: > "m...(a)sushi.com" <m...(a)sushi.com> wrote: > >On May 7, 2:13=A0pm, 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=3D2778 > > >> 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. > > Well... a good HP3314A still sells for a couple of hundred. More > recent Agilent generators fetch even more. AFAIK those are USB and/or > ethernet controllable. > > -- > Failure does not prove something is impossible, failure simply > indicates you are not using the right tools... > nico(a)nctdevpuntnl (punt=.) > -------------------------------------------------------------- The HP3314A has a control panel, so it's not like you are buying a black box USB device from a Chinese company that won't exist in a few years. Black boxes can become bricks if the drivers are history. Think about all the ISA controlled items that have become bricks. ISA GPIB boards are valueable only for their trade in value with Nation Instruments. Anybody need a scsi drive? Now ethernet is another story. It doesn't need drivers. I've seen the similar Fluke or Tek function generator that cuts out at 11Mhz go for about $200. I think Joerg's issue is a lack of local geeks. ;-) In the bay area, these items are very common on the used market. Probably LA as well.
From: Paul Keinanen on 9 May 2010 00:05
On Fri, 07 May 2010 16:17:18 -0700, Joerg <invalid(a)invalid.invalid> wrote: >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. Indeed, the USB isolator and a self powered USB hub would be quite nasty. Perhaps a miniature laptop with big batteries could be floated with the test equipment, but the stray capacitances could cause problems. Doing measurements with the test system floating on the mains voltage would also be dangerous. |