At 02:13 PM 6/18/2007, David Gilbert wrote:
>Wouldn't it be simpler to design a proper line driver that would
>interface the SteppIR controller to a long cable?
Actually.. I think it would be better to make the "power handling"
wires the short ones, and the "information handling wires" (the RS232
connection) the long one. Rather than try and develop and build 8
drivers (2 coils for each of 4 steppers), just buy an off the shelf
long distance serial connection.
Putting the SteppIR controller at the base of the tower is a nice
compromise between short wires and accessibility for servicing. Put a
Hoffman enclosure there, and you're basically done...
Just in cable costs alone you'd save money: running a serial port
500ft takes two pair phone wire or something like cat5 cable, which
is very cheap. Hundreds of feet of 16 conductor cable is a fair
investment in copper alone.
You can remote an RS232 with a variety of off the shelf line
driver/longhaul modem widgets using either twisted pair (RS422) or
optical or RF (Mouser sells, among other things, little Radiotronix
modules that use RF to send RS232 long distances). Or, you can run
ethernet out there (using 802.11?) and use a ethernet to serial
converter. 400 ft is a long run with Cat 5, though...
The question would be whether there's some "front panel" features of
the SteppIR that you need that cannot be suitably replicated in the
shack. (push buttons, indicators, etc.).. Ideally, it would be all
"off the shelf" stuff (sure, one can speculate about a PIC that reads
buttons and lights LEDs and talks via the RS232 interface, but that's
a whole project in itself).
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