Re: L297 / L298 Help Required Pls!

Not sure whats happened to the diagram that took me forever to
create.... It looked ok in the preview.. :-(

It's looks ok when you post a reply...!

Must be the advertising on the righthand side screwing it up...

Steve


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "paragon032003" <sme@p...>
wrote:

> Sorry for not replying back sooner I have been away for a couple of
> days....
>
> Ok Ill try and explain more clearly ....
>
> The stepper controller is using 12v at the Step / Dir pins on the
> euro connector.
> The Step/Dir on the L297 is at 5v so this is OK.
>
> The voltage is always High (12V) on the Step/Dir of the euro
> connector on the stepper card.
> What I think I need to is sink the 12v to ground producing a LOW.
>
> I have seen some circuits on the web that look like the below....
>
> 12v
> Step (from Eurocard)
>
> |
> |
> B | /C
> D0 --------R1K------|/ TR1
> |\
> | \E
> |
> |
> R
> |
> |
> ------------------------ Gnd
>
>
> Now from what I understand .. When D0 is High (5V) it basically
> grounds the Collector input (Step 12V) thus sending it Low.
> Now what I want is the reverse to this i.e. when D0 is low it the
> Step (12V) goes Low and when D0 is High (5V) the Step (12V) is High
> i.e. at 12V.
> Ideally an opto-coupler would be sitting between the Parallel port
> and transistor.
>
> Hope this explains a little more.
>
> TIA
> Steve
>
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, RichD <cmsteam@s...> wrote:
> > Steve,
> > You have to fill in more detail.
> > Where exactly are you checking this 0-12V?
> > At the output of the L298? or the input of the L297?
> > The L297's are 5V logic devices only.
> > The input to the L298's are too, but the outputs (motor coil

drives)

> > are whatever the motor supply voltage is. Is this the 12V you
> mention?
> > The outputs (motor coil drives) are phase drive and will seem

weird

> > to see a correspondence to the step input.
> > Otherwise, I see no problem so far.
> > What IS the problem you have? Does the motor not step with step
> input pulses?
> > RichD
> >
> >
> > paragon032003 wrote:
> > >
> > > John / Rich
> > >
> > > Thanks for your reply's!
> > >
> > > This is what I have found since the original post...
> > >
> > > The stepper driver cards are running at 12V for hi.
> > > On the logic board there are three ILD74's (Dual opto

transistors)

> > > these are accepting between 0-3.5V Lo/Hi respectively its set
> high by
> > > default then pulses down to low (step takes place) then back to
> hi on
> > > the output side a single pin reads 12V and pulsates down to 0
> this is
> > > connected to the stepper drives the DIR side is the same but
> toggle
> > > between high and low (high = Clockwise).
> > >
> > > Does this make any sense?
> > >
> > > I presume that when the logic side goes low it sinks the 12V

side

> to
> > > ground via a resister this then produces a low.
> > >
> > > Does this sound likely?
> > >
> > > TIA
> > > Steve.
> > >