Wishlist for the next drive (describe your dream drive!)

[Xerxes]

Greetings everyone!

I'm starting to design the next drive that should be available in some point 2008.

Target specs in short:
-Supply voltage range 12-80 Vdc
-Output current 10A cont, 20A peak
-Discrete MOSFET power stage
-Fourth power output pin for 2-phase stepping motors
-Card-like construction that can be installed in control box wall without intermediate wiring from drive to back panel
-Sub-D connectors for motor windings and encoder
-Short circuit & overtemp protections
-99% based on VSD-A firmware but adds couple of new features

It is not replacing VSD-A but is merely an addition to drive selection (a low voltage version with premium stepper support).

I'm asking you folks whether you have some ideas to be added/changed in this drive compared to VSD-A :-) It would be very helpful if you described your "dream drive" for your particular needs.

Thanks,
Tero

[Eson]

How about a FPGA drive with open source software? You could support both 2- and 3-phase servos/steppers and all kinds of encoders.

[Xerxes]

Eson, thank you for sharing the thoughs. FPGA is an interesting approach but is not required to meet these requirements. The drive will support AC/BLDC/DC/Stepping motors and differential & single ended encoders.

Anyone interested about 3-phase stepper support? It could be added but 3ph steppers are quite rare so I don't know if its worth it.

[Episs]

how about modular design by using separate power stage from the board then thous who have small motors could use cheaper power stage than for higher power motors + could support more motor types by changing power stage and firmware. same thing could be with encoder feed back, you could support also sinusoidal encoders .
+ your main board could be multiaxis.

[Eson]

I belive support for more encoder types are one of the most wanted.
Time will tell.

[Xerxes]

Modularized encoder receiver actually has been in my plans for some distant future drive. It could be a small PCB that is connected to main board.

I have been thinking modular drive a lot. However, some compromises would need to be made compared to a monolithic design. Alternatively we could make a drive with only logic section so desired kind of power stage could be supplied by customer. However, that could generate large amounts of support request if inexperienced people would start building power stages themselves. There is nothing wrong in support requests if there is enought time to handle them

[Al_The_Man]

Originally Posted by Xerxes -Sub-D connectors for motor windings and encoder

Is that wise to spec in a sub D connector for motor windings? especially for 10a+.
I wouldn't trust a D connector at that current.
Al.

[Xerxes]

Originally Posted by Al_The_Man Is that wise to spec in a sub D connector for motor windings? especially for 10a+. I wouldn't trust a D connector at that current. Al.

I'm planning to use D25 connector so one phase gets 6 pins in parallel. Typical connectors have specs of 300V and 3A per pin, so in parallel it would equal 18A cont per phase.

[Al_The_Man]

I am just questioning the logic as to what you are saving over say a single screw terminal connection, this would mean terminating 18 wires into the D connector for each motor?
At some point I assume the motor itself will have 3 wires or connections, so each 6 conductors will have to terminate to a single connection, or am I missing something?
Al.

[Xerxes]

I like D connector because it has mechanism to secure cable position by screws and connector nuts can be used to mount card on enclosure wall (just like PC cards are connected to L-shaped sheet metal part).

You could still use the same low pole count cable and just solder it to multiple pins at connector end.

Also hybrid D-sub connectors exist for high currents but those are harder to find and are quite expensive, too.

[PaulH]

Why not use something like an Anderson Power Products connector? The PowerMod series is rated for 30A per pin, can only be plugged in one way, and can be circuit-board mounted.

http://www.andersonpower.com/product...onnectors.html

[Xerxes]

Paul, that kind of connectors seem to be quite good alternative. However, these too are non-standard and harder to find for user. I have put that kind of connectors in my CNC drive box and they're quite good indeed. But I still missing the possibility to mount card on enclosure with these.