Re: New servo drive development

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "rutexusa" <rutexus@...>
wrote:

>
> Gentlemen,
>
> I am getting close to finishing a new DC Brush servo drive that I
> have been working on for the last six months which will be mother
> board connectable to both Rutex R9x0 series and R2000 series
> motherboards operating in step and direction mode, but will have
> more "whistles and bells" and features to help customers use them.

I

> am not ready to give out details yet, but I'd like some input from
> users. I am specifying three different methods of stopping the
> drive:
>
> 1. Stop and hold input signal
>
> 2. Stop and freewheel input signal.
>
> 3. Stop and hold on hard fault.
>
> I am thinking of having all hard faults do a "stop and hold" in

which

> the error flag would be resettable with a short pulse on a reset
> signal, and if a long reset pulse is received on the reset line,

the

> drive would reset both encoder and position counters to zero as

well

> as reset the fault.
>
> The question: Would it be better to have a hard fault condition do

a

> stop and hold in position or stop and freewheel--in other words,
> would it be better to prevent the drive from allowing the axis and
> motor to coast or hold firm? Safety is a concern.
>
> A hard fault would be caused by excessive current drawn, high
> temperature in the drive, excessive following error, or other
> internal issues that the drive would fault on that I don't care to
> mention right now.
>
> Note that the drive should also employ a warning output signal

which

> will warn if current is marginally high, or following error

reaches a

> certain level (but not critically high). This output signal will

not

> stop the drive, but provide an output from the CPU on the drive

that

> could be used to either light a flashing LED warning or as a

warning

> signal to a cnc control to slow down the step pulse rate or

whatever

> error handling routine a control might employ. This warning signal
> will reset itself as soon as the condition is removed.
>
> The Drive PID is working fairly well, but the error handling has

not

> been settled on so, if any would like to give their imput, I'd
> appreciate hearing from you.
>
> I am developing this drive considering things I have learned from

my

> experience supporting the Rutex drives these last few years.
>
> The drive will be announced on a web site that my sons are putting
> the mach3 packages they are developing. You might want to take a
> look there too: www.machmotion.com. I hope to have some to sell in
> a couple more months. It is my full time project now so I want to
> wrap it up. I have nothing else on my plate for several months!
>
> Thanks for any advice you care to give.
>
> Tom Eldredge
>

Hi Tom,
As a rutex drive user, this is what I think:
1- Stop and hold and send a error signal out and a reset input
without resetting the encoder position.
2- Some sort of led Bargraph ( maybe three or 5 leds) to monitor
current.If there is no place on the board, there should be pins
avaiable to plug the leds to it.

Fogassa