Re: port problem

Terry,

This is even simpler, Try it!

If you have an external +5 volt supply, you have two options: use the
Data
Out pins to sink up to 24 mA from your +5 volt supply, or use buffer
chips
to control (source or sink) more current (or higher voltages). I have
used an external 5 Volt supply (regulated wall wart) plus optocoupled
solid
state relays as the "load", to control AC voltages (keep the high AC
voltages
away from any of this logic level stuff, obviously).

+------------------------------- (+5 v)
|+
Sinking Load (up to 24 mA @ 4.2v)
|- Power Supply
Dn Out ------+

Ground -------------------------------------- ( Gnd)

Alan

Terry Ackland wrote:

>
> --- Alan,
> thanks for the response. I just connected pin 1 of the port to the
> plus of the relay and the minus on the relay to pin 18 of the port.
> No good?
> Terry
> In CAD_CAM_EDM_DRO@egroups.com, Alan Marconett KM6VV <KM6VV@a...>
> wrote:
> > Terry,
> >
> > I don't know how you're wiring the SSrelay, but you might just need
> an
> > open collector transistor to drive the SS relay. Most parallel
> ports
> > can SINK more current then they can SOURCE. Are you using the
> "active
> > low" level to drive the SS?
> >
> > Alan
> >
> > Terry Ackland wrote:
> > >
> > > Guys,
> > > I have finally got around to connection up the recommended relay
> > > (CX240D5) to my parallel port and a spindle but I am not having
> any
> > > luck.
> > > I can turn the 5 volts on and off using M-codes but there does not
> > > seem to be enough current to operate the relay. It was mentioned
> in a
> > > previous post that a new parallel port board would be needed if
> there
> > > was not enough current available. Would someone advise me on the
> > > particular board and what should I ask for when ordering one? I am
> > > using an old 386 which is fast enough for what I need.
> > > I also have a backup 386 that I picked out of the garbage, it
> works
> > > fine but the pins switched by M-codes are always on even when
> > > instructed to turn off so I think 2 boards are should be ordered?
> > > Thanks, Terry Ackland
> > >