re: Stepper motor transition board

[RIVERS@BNLX26.NSLS.BNL.GOV (Mark Rivers)]

Guy,

> We are thinking of laying out  a PCB to simplify the connections between an
> OMS and a StepPak, instead of the hand wiring currently suggested.

> We're envisaging a simple 4U transition card with the VME J2 connector on one
> side and two StepPak connectors on the other.
> It would go in the rear bay of the VME crate with a ribbon cable connection
> between the backplane and the transition card.   The same card could also go
> into the front of the VME crate if you linked two adjacent J2 connectors on
> the backplane.
> Any comments?

I was thinking of doing the same thing. However, Karen Coulter told me that it
has already been done at Los Alamos. Karen, can you get the info and perhaps
find if we can get the PC layout file?

If you do end up laying out a new board I would like to suggest the following:

- Include 1 uf capacitors between each of the limit switch lines and  ground.
These will eliminate glitches on the limit lines. These can be  a real
problem, at least when used with E500 controllers. I don't know  if the OMS
controllers are any less sensitive to these glitches. 

- Provisions be made to optionally allow the motor  pulse signals to be
brought out to BNC or LEMO connectors on the front of  the transition board.
This will make it easy to use the motor pulses to drive the channel advance
signal of a multichannel scaler, as we did in our scanning microscope demo. 

- Provisions be made for optional circuity to convert the  pulse/direction
output of the OMS board to pulse/pulse (CW/CCW). This would allow the OMS
board to drive controllers which require pulse/pulse, for example the Klinger
DC motor driver module.

                                   Mark