Re: cheaper I/O for EMC
Posted by
Jon Elson
on 2000-05-10 22:17:22 UTC
Paul Devey wrote:
is to use the
facilities of RS-1284 (a parallel-port standard for improved throughput)
to control
a flexible array of boards, including D/A converters, encoder counters
and digital
input and output. I am designing a 4-channel, 16-bit DAC board and a
4-channel
quadrature encoder counter. The DAC board should be well under $100
(parts cost is looking like $50 - $60 right now) and the encoder counter
looks like
one $18 chip on a board (unless you need differential inputs, which adds
3 more
$2 chips). I haven't really defined the digital I/O yet, but something
like 24 bits of
input on one board, and maybe up to 16-bits output on another (the Solid
State
relays are bigger than the input optocouplers). These boards should be
VERY
cheap, with one $6 CPLD and the optocouplers or SSRs, and not much else.
I am planning on putting the optocouplers and SSRs right on the control
boards,
eliminating separate opto boards and associated wiring. All the boards
would
be connected to a 37-conductor ribbon cable by standard IDC connectors.
This cable would be the parallel port signals plus some additional wires
for
power supply and communication between boards.
The boards would have address switches on them, so you could set the
addresses
depending on how much of each type you needed. Of course, the simple
machines
would only need one of each.
Jon
> Guys,I'm doing this, in coordination with Matt Shaver. The general concept
>
> I am all for porting this puppy over to my fav. OS LINUX. However, I
> am
> concerned that if people have to purchase new controllers, expensive
> ones at
> that, we may slow down the "market" acceptance of this product.
>
> What about designing a parallel port controller that has an external
> interrupt to clock activities. Greg Nuspel and Hans Weidermeyer have
> designed such controllers. They could be made easily by hobbyists, Dan
>
> Maunch etc.
is to use the
facilities of RS-1284 (a parallel-port standard for improved throughput)
to control
a flexible array of boards, including D/A converters, encoder counters
and digital
input and output. I am designing a 4-channel, 16-bit DAC board and a
4-channel
quadrature encoder counter. The DAC board should be well under $100
(parts cost is looking like $50 - $60 right now) and the encoder counter
looks like
one $18 chip on a board (unless you need differential inputs, which adds
3 more
$2 chips). I haven't really defined the digital I/O yet, but something
like 24 bits of
input on one board, and maybe up to 16-bits output on another (the Solid
State
relays are bigger than the input optocouplers). These boards should be
VERY
cheap, with one $6 CPLD and the optocouplers or SSRs, and not much else.
I am planning on putting the optocouplers and SSRs right on the control
boards,
eliminating separate opto boards and associated wiring. All the boards
would
be connected to a 37-conductor ribbon cable by standard IDC connectors.
This cable would be the parallel port signals plus some additional wires
for
power supply and communication between boards.
The boards would have address switches on them, so you could set the
addresses
depending on how much of each type you needed. Of course, the simple
machines
would only need one of each.
Jon