Just a quick update of ION servo drive development: all hardware peripherals are now programmed and functioning properly and all hardware “typos” are corrected in the schematics & PCB layout. This is important milestone as now we can preparing the first production batch of hardware even when firmware is not fully complete. Firmware development will continue on prototype while we wait hardware from fabrication.
Meanwhile, I have been pondering how to make the higher power version of ION. Some options are:
- ION with 84 pin card edge connector (now 64 pin) and larger power stage. This can yield approx 10 A 90 VDC capability (limited by card edge connector).
- Add external power connector to ION. This eliminates card edge connector current & voltage but might would look weird and impractical. Also fitting large power stage on the board could be difficult.
- Get rid of card edge connector and replace all with wire terminals. This would easily give highest voltage & current rating but would not get benefit of ION motherboards, so wiring work would increase significantly. This option would look like updated VSD-E.
Which one sounds preferable to you? Leave a reply in comments :)
Something like a updated VSD-E and a downgraded Argon will match perfectly :)
Yes, that is exactly the plan! Only question is what it will look like :)
I prefer the longer cardedge connector, because it is far tidier when using more than one board.
How about making a supplemental board available that has just the socket and screw terminals? That would let people convert very easily.
Also +1 on using standard PCI Express connectors.
Any rough idea what the price class for these babies might be?
Finally, on your site, years ago
“http://www.students.tut.fi/~kontkant/servodrive.php.html”
you stated “I’m switching from dsPIC to Freescale DSC’s. ”
I am very curious why you did that. Those PICs seem very capable, include hardware for the quadrature signals etc.
Nice to see people liking the card edge & motherboard concept! Do you mean screw terminal to card edge converter for VSD-E compatibility?
It’s too early to guess prices, but Ion series will be aggressively priced. See: http://openservodrive.com/first-ion-servo-drive/#comment-1287
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Decision to switch from dsPIC had several factors. One was development tools and second was the features and performance of chips. Back then dsPICs were available only at 30 and 40 MHz while Freescales were 60 and 80 MHz and also ADC was better in the latter.
I did mean a screw terminal to card edge converter, but not necessarily for any compatibility reasons. Some people may not like the motherboard concept and a simple adapter gives them a more traditional option. I do think 700W is just fine, but everybodys’ needs are different.
Maybe similar in principle to this:
http://www.ulrichmodels.biz/servlet/the-688/Tortoise-Screw-Terminal-Card/Detail
Isn’t it possible to just put holes for a terminal strip right above the card edge and not populate it? If anyone wants the terminals, he could simply populate the terminal strip (or solder the wires directly). Terminal would then physically rest on the card edge ( so you can’t necessarily plug it into the PCI Express connector any more, of course). Should only add 100-150 mils or so to the dimension of the board.
Ah, I see. Of course that kind of adapter will be trivial to make. For high current needs, one solution would be to just cut a slot on PCB and sodler card edge drive to it but I doubt many would not like that.
Sure it would be possible to make pin strip holes on PCB but pin strip connector is not much better than card edge connector what comes to power rating. PCI-e connector has spec of 1.1A per pin (continuous).
With regards to the holes, I mean to allow the soldering in of the high power green connectors you put onto the argon, like here:
http://openservodrive.com/wp-content/uploads/2013/01/argoncover_m.jpg
for power.
Best option for bringing out signaling lines would depend on the size of the board, of course. I was focusing about getting the large amount of power out, since you brought that up as primary concern. This way, you have a single device that covers a larger power range, but the user has to solder on terminals (or the wires directly into the board) to get the high rating. Just brainstorming…
Also, can’t wait to get my hands on an ION board of any type to play with…..
Jan, that is actually one option I’we been pondering. Board could have holes where wires or high current connectors could be added by those who need them.
Hi
All contacts with a high current and high voltage to the individual ION cards is definitely the very best. ION motherboard please only for data! Such a solution would not look strange. A bit strange is the idea to carry high currents through the bar. My suggestion could also be the best business concept for you: Do you offer only ION motherboards with 5 slots at a good price, but without power management. Power management exclusively for individual motors on each small ION plug-in card. The customer will fill them gradually! Again: in the other case, you will always ask yourself whether the current-carrying plug contacts corrode or get hot at some point.
Best regards from Klaus from Herford (Ger)
Thanks for your thoughts! Power through card edge should work up to some power levels very well but much beyond 700W it may become a bit impractical. If it was only for data, then same thing would be possible with ribbon cable connection (just like VSD-E was connected to VSDEPI board).
So the first question really should be how much current and voltage people really need. Once the specs are clear, then the connector solution becomes easier to choose. Options are roughly like:
Card edge only: 700 W
Card edge + terminals: up to 1 kW
Terminals only (large PCB): 1.5 kW
My personal requirement is 40A and 55V.
Regards, Klaus
Hi Tero,
It seems to me the best option would be an updated replacement for the VSD-E. You’ll have the low power ION fulfilling the 0-500 watt(?) segment, ARGON works for larger AC powered machinery, leaving a gap where VSD-E was.
I’d most like to see a 1.5Kw version or higher. There’s also very little available in lower voltage, higher current servo drives anywhere. I’d REALLY like to see them stackable to increase current rating as you have done for the Intensify Nx50, so we can offer a 30-40 amp drive. That would be useful for the DC motor people, but also for others like myself who use who use larger direct drive motors in various applications. At the moment we use VSD-XE (until I run out!), but we are giving up a lot of torque on these motors that can take 50+ amps. Argon doesn’t offer any advantage here as we don’t need any more speed, and it’s much bigger and costs more too of course.
Incidentally, I replace the green power connectors on the VSD-E with WAGO 2092-1376 terminal blocks. The wiring is much quicker and they hold much better than the screw terminal blocks (although the pin headers are barely long enough). If we could have a similar solution for wiring the DC power and motor outputs that would be excellent :)
Kind regards,
Jason
I forgot to add, the card edge connector forces the customer to use the motherboard whether they want to or not. It may push some customers away, particularly those whose application requires a single drive. Optimally, a solution that would allow the customer to chose whether to use the motherboard or not would be best, but please make it possible to use the drive without it.
Thanks :)
Jason
Thanks for valuable feedback Jason!
Small Ion with card edge connector is just the beginning and the plan is to fill the gap one way or another. After small version is ready, then making different variations with different power stage and connectors are quick jobs.
I’m motivated to make careful choices there which way to implement the variations as we don’t want end up managing 15 different models. 2-3 Ion based models should be enough.
Paralleling multiple motor drives is far more complicated than DC current sources (Nx50). If it would be easy, it would have been done already. The easiest thing is to make paralleling inside one drive (like VSD-E parallel DC mode) and that is probably going to be available in Ion series too.
The paralleling of AC drives is possible since years. I’ve seen it with drives, I’ve participated in the development. And I mean standard drives – got out from the box. It was in 2007 with 2×80 KW drives in order to supply one single 160 KW PMSM. You just need the right synchronization between the drives.
Yes its possible but takes time to implement it. Technically it needs some dedicated wire where PWM time bases are synced accurately and data connection where duty cycle values and current sensor readings are transferred between master and slave drives.
Real time requirements for this are very tough so it probably needs a separate communication channel apart from user accessible port (i.e. Simplemotion). It’s absolutely necessary that duty cycle changes simultaneously on all parallel drives so any timing uncertainty in communication bus is bad.
But I’m not saying it won’t ever come to GD drives :)
Most companies that make PCB mount drives are using through hole pins (e.g. AMC, Elmo, Copley, PMD). The PMD Atlas drives are really cute. Some companies do take the card edge approach, such as Technosoft’s iPOS line which offers up to 8A/20A at 50V.
BTW, PMD has been making their ION line of digital drives for a long time (I happen to own one), and it is trademarked, so if you ever have a bigger US presence you’ll have to pick a different name for the US.
Another approach is to use board to board connectors designed for power or power and communications from companies such as TE, Molex, Samtec, and Positronic (the Mouser and Digikey catalogs are good starting places). These can handle large currents (20A, 35A, 50A or more), but of course can get pretty pricey. I’m pretty sure the rack-type systems (with plug in drives) from companies such as Delta Tau, ACS, and Aerotech use this approach.
Thanks Tony! Good to see we’re not the only ones making miniaturized drive, which tells me there is market for them :)
I wasn’t aware of the PMD ION. It’s definitely good idea be prepared to switch the name.
We will use connectors that are widely available and inexpensive for obvious reasons. Standard screw terminals handle tens of amps and hundreds of volts, which are the choice for over 1kW.
Hi, IMO you maybe should try to do a version of ION directed to simracers a derivation of ION non pcb, that only need 1 motor to be driven, there is an oportunity of business there i think, there are some diy projects going on that are using a servo motor to play and they mostly are using your vsd or argon drives, a cheaper drive with limited functions the only ones required for these projects would be nice, i myself im interested on this as simracing is one of my hobbies, would like to see something like this.
I love the racing simulator projects. This would be easily doable with the idea provided here by Jan. A simple card-edge to wire terminal breakout board makes nice single axis drive from Ion.
Let me know if some special features would be helful and I’ll be happy to evaluate them!
I like the idea of a motherboard, but can live with wire terminals if necessary. 700W is plenty for my needs. For axes needing 1.5kW I would probably add an Argon.
Good to hear that! It is also plan to make Ion and Argon integrate nicely (i.e. same RJ45 cable going thru all) so mixing them would be no issue.
Could it be as simple as using 2 PCI connectors? It would make the card longer, but keep compatibility (you could still plug a double ION into a single slot, but would have only half the current). Does that still limit it to 90V?
Maybe some of these:
http://datasheet.octopart.com/5530843-4-Tyco-Electronics-datasheet-11080852.pdf
I really am looking forward to a VSD-XE equivalent – 160VDC & 18A cont. 40A peak.
I would take any connector that would provide that.
The original idea I had in mind was to use a 8X PCI-e connector for high power version. It adds 34 pins which could be used for power. This would allow compatibility for different models because 4X PIC-e card fits to 8X slot as well.
The Tyco high power connector looks very promising! Thanks! I’m thinking that this kind of connector could be placed at the end of PCE-e connector just to give more current carrying capability (38 A according to specs, and high voltage too):
http://www.digikey.com/product-detail/en/1888946-2/A107677-ND/4021558
I like it a lot! I think the edge connectors are a great idea.
Motherboards would sure simplify building a controller.