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From: John Larkin on 30 Jun 2010 16:50 This is the 12-channel isolated 4-20 mA thing, the one with 13 100-MHz ARM processors on the board. ftp://jjlarkin.lmi.net/V220_top.jpg All we have to do now is get it to work. John
From: Jan Panteltje on 30 Jun 2010 17:01 On a sunny day (Wed, 30 Jun 2010 13:50:12 -0700) it happened John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in <46bn26tjj3bm5b8bsfsp0ee7a9efvb72vl(a)4ax.com>: > >This is the 12-channel isolated 4-20 mA thing, the one with 13 100-MHz >ARM processors on the board. > >ftp://jjlarkin.lmi.net/V220_top.jpg > >All we have to do now is get it to work. > >John http://www.allfavorpcb.com/ ?
From: John Larkin on 1 Jul 2010 12:44 On Wed, 30 Jun 2010 21:01:04 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >On a sunny day (Wed, 30 Jun 2010 13:50:12 -0700) it happened John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in ><46bn26tjj3bm5b8bsfsp0ee7a9efvb72vl(a)4ax.com>: > >> >>This is the 12-channel isolated 4-20 mA thing, the one with 13 100-MHz >>ARM processors on the board. >> >>ftp://jjlarkin.lmi.net/V220_top.jpg >> >>All we have to do now is get it to work. >> >>John > >http://www.allfavorpcb.com/ ? We ordered the boards from Phase 3 http://www.p3ti.com/ who apparently brokered them to Allfavor. We ordered four boards, quick turn, electrically tested, 6 layers, screened both sides, 8/8 rules, for $175 each. I guess it's cheaper to email the gerbers to China and fly the boards back, than to make them here. That's a pretty good photo, for hand-held. The Allfavor bug is pretty small. That's not even the original full-res picture. The silkscreen reference designators are 60 mils high and are nice and sharp. It seems to work so far. No assembly problems, just one complaint about a bottomside part that can't be glued so has to be hand soldered. The twelve isolated channel power supplies are fine, and we're talking jtag to the ARMs and blinking LEDs. We'll test the analog stuff today. To power the 3 volt ADC reference bandgaps in each channel, I fudged the 3.3 volt supply up to 3.5 and just used a resistor. I did suggest a beta-limited PNP current source, to predictable squealing, but that would have been one more part for about the same performance. LM4040s aren't very picky about operating current. I wrote the manual (21 pages so far, more to come) and a 16 page design notes document, so my software guy has all the input and math he needs to program the ARMs. We'll release the design doc to the library for future reference. John
From: Jan Panteltje on 1 Jul 2010 14:49 On a sunny day (Thu, 01 Jul 2010 09:44:48 -0700) it happened John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in <r0gp26d6soituurqdhc1bkqquunfpos1de(a)4ax.com>: >>http://www.allfavorpcb.com/ ? > >We ordered the boards from Phase 3 > >http://www.p3ti.com/ > >who apparently brokered them to Allfavor. We ordered four boards, >quick turn, electrically tested, 6 layers, screened both sides, 8/8 >rules, for $175 each. That is a good price, and it helps to have a contact in your own country. >I guess it's cheaper to email the gerbers to China and fly the boards >back, than to make them here. > >That's a pretty good photo, for hand-held. The Allfavor bug is pretty >small. That's not even the original full-res picture. The silkscreen >reference designators are 60 mils high and are nice and sharp. I had trouble reading the text on the IC packages, could hardly make out 'Xilinx' in the big one at top pright. Did you erase the text or all all those chips that way? >It seems to work so far. No assembly problems, just one complaint >about a bottomside part that can't be glued so has to be hand >soldered. The twelve isolated channel power supplies are fine, and >we're talking jtag to the ARMs and blinking LEDs. We'll test the >analog stuff today. Does it run hot? >To power the 3 volt ADC reference bandgaps in each channel, I fudged >the 3.3 volt supply up to 3.5 and just used a resistor. I did suggest >a beta-limited PNP current source, to predictable squealing, but that >would have been one more part for about the same performance. LM4040s >aren't very picky about operating current. > >I wrote the manual (21 pages so far, more to come) and a 16 page >design notes document, so my software guy has all the input and math >he needs to program the ARMs. We'll release the design doc to the >library for future reference. Yes sometimes he documentation is even as much work or more then the design, I remember one requirement from gov: All parts must be addressed in the docs. I am impressed by the 'fill rate', I mean how much you got on that bord. Hope it works, >John > > >
From: John Larkin on 1 Jul 2010 18:12 On Thu, 01 Jul 2010 18:49:27 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >On a sunny day (Thu, 01 Jul 2010 09:44:48 -0700) it happened John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in ><r0gp26d6soituurqdhc1bkqquunfpos1de(a)4ax.com>: > >>>http://www.allfavorpcb.com/ ? >> >>We ordered the boards from Phase 3 >> >>http://www.p3ti.com/ >> >>who apparently brokered them to Allfavor. We ordered four boards, >>quick turn, electrically tested, 6 layers, screened both sides, 8/8 >>rules, for $175 each. > >That is a good price, and it helps to have a contact in your own country. > > >>I guess it's cheaper to email the gerbers to China and fly the boards >>back, than to make them here. >> >>That's a pretty good photo, for hand-held. The Allfavor bug is pretty >>small. That's not even the original full-res picture. The silkscreen >>reference designators are 60 mils high and are nice and sharp. > >I had trouble reading the text on the IC packages, could hardly make out 'Xilinx' >in the big one at top pright. >Did you erase the text or all all those chips that way? That's the way most chips are these days. I think it's laser marking on the epoxy. If the illumination is straight-on, the markings are just about invisible. There are three SSRs, upper left, that actually have silkscreened part numbers, and whose markings are visible with most any illumination. > > >>It seems to work so far. No assembly problems, just one complaint >>about a bottomside part that can't be glued so has to be hand >>soldered. The twelve isolated channel power supplies are fine, and >>we're talking jtag to the ARMs and blinking LEDs. We'll test the >>analog stuff today. > >Does it run hot? It shouldn't, at least until we get the 4-20 mA stuff running. Each channel can dissipate up to 700 mW of loop power. With just the CPUs and stuff running, everything is cool. VME crates have lots of fans. One thing I do on a new board is feel all the parts to see if anything is warm. > > >>To power the 3 volt ADC reference bandgaps in each channel, I fudged >>the 3.3 volt supply up to 3.5 and just used a resistor. I did suggest >>a beta-limited PNP current source, to predictable squealing, but that >>would have been one more part for about the same performance. LM4040s >>aren't very picky about operating current. >> >>I wrote the manual (21 pages so far, more to come) and a 16 page >>design notes document, so my software guy has all the input and math >>he needs to program the ARMs. We'll release the design doc to the >>library for future reference. > >Yes sometimes he documentation is even as much work or more then the design, >I remember one requirement from gov: All parts must be addressed in the docs. > > >I am impressed by the 'fill rate', I mean how much you got on that bord. It has parts on the back, too! >Hope it works, Yeah, it's always a little tense before it works, hoping there's no fatal blunder. John
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