Hi Robert - I made my own.
I use Amplified photo home switches, which in and of themselves are
optoisolated, my limits and estop go thru 4n25s, my step & dir line go thru
a filter/ amp/ inverter, and opto inverted gate at ultra high speed, and my
spindle & Vac controls are SSR'd..
Nobody offered this type of B.O.B. yet, you should look into it , isolate
those S&D lines. I have not had a single lost step since I did it.
JT
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----- Original Message -----
From: "Robert Campbell" <bob@...>
To: <mach1mach2cnc@...>
Sent: Wednesday, March 10, 2004 10:36 PM
Subject: Re: [mach1mach2cnc] Re: Limit switch wiring
One of the advantages of using the Sound Logic breakout board is that it
includes an optical isolator on the input. The optical isolator in effect
eliminated the very short false triggers. You can use either inductive
proximity sensors or micro switches.
Bob Campbell
Bob@...
www.campbelldesigns.com
Breakout board
THC board sets
CNC router plans
Stepper Motors
----- Original Message -----
From: "Jeremy Taylor" <jt@...>
To: <mach1mach2cnc@...>
Sent: Wednesday, March 10, 2004 9:26 PM
Subject: Re: [mach1mach2cnc] Re: Limit switch wiring
I use 10Ks with no problem, the reason is to supply a positive "Pull Up"
to
the ttl signal, you only need a little bit of power, so 10K works fine,
Without them, you run the risk of false triggers. When the NC switch is
closed, it provides a path to ground, so the pin looks low, when the NC
is
broken, the pin goes high, as ground is broken and the power thru the
resistor provides the +.
Without a resistor, with NC switches, the possible problems (baring a
massive short circuit) is false triggers, or wasted power, and possibly
overworking the par port, which according to spec can only source/sink
MAX
<1A of current .
JT
----- Original Message -----
From: "george_barr" <george_barr@...>
To: <mach1mach2cnc@...>
Sent: Wednesday, March 10, 2004 10:02 PM
Subject: [mach1mach2cnc] Re: Limit switch wiring
I am using a proximity switch in NC mode. I do not use any resistor
(e.g. 4.7k) and it still works. Do I need a resistor for my limit
switches and what are the advantages/disadvantages with using a
resistor?
Thanks,
--- In mach1mach2cnc@..., "andrebarclay"
<andre.barclay@v...> wrote:
I'm trying to finish up my gantry router and I'm at the limit switch
part. Here's what I was thinking of doing. Take the 5v from the pc
and run it through a 4.7k resistor to a NC limitswitch and then to
the
11,12, or 13 pin on the port. Does anyone know if this will be a
problem and if there is a better setup? I thought it would be
better
to ask than to cry.
Andre
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