On Sun, 19 May 2019, Nicklas Karlsson wrote:
Date: Sun, 19 May 2019 18:27:44 +0200
From: Nicklas Karlsson <[email protected]>
Reply-To: "Enhanced Machine Controller (EMC)"
<[email protected]>
To: "Enhanced Machine Controller (EMC)" <[email protected]>
Subject: Re: [Emc-users] Unusual help request.
On Sun, 19 May 2019, Davide wrote:
Date: Sun, 19 May 2019 16:26:26 +0200
From: Davide <[email protected]>
Reply-To: "Enhanced Machine Controller (EMC)"
<[email protected]>
To: [email protected]
Subject: [Emc-users] Unusual help request.
Hi, I have a strange setup to solve. So I'm asking you an help, on the top
of your knowledge (sorry for any language mistake) Some time ago I have
built an inverted wire tetrapod, which was made by 4 winches placed at a max
distance of 20 meters one each other in a rectangular shape. So until now it
was ok to have a 48v 20A DC power supply and a parallel bob near my pc (an
asrock q1900b-itx), and transmit step/dir signals thru ethernet cables to
the stepper drivers inside the winches.
Now I have to modify that to make a very little object fly inside a soccer
arena, so the motors will be placed at 80 meters one each other, and i'm
really worried that a step every 10 will arrive to the drivers, if any at
all.. The further motor will be at 150mt if I'm lucky..
An idea can be a mesa ethernet card, but I should use 4 of them, so I'm
asking you if you think is possible to make 4 of them work with linuxcnc?
Another can be convert in some way step dir signals to optic fiber
transport. But i couldn't find anything to buy.
Any other suggestion?
Thanks, Davide.
150 meters is no problem for 100 KHz RS-422 (Spec is 1220 meters at 100 KBPS
~= 50K steps/second) So just using good line drivers/ receivers should be fine
It may even work with differential drivers and normal opto-isolated step motor
drives driven differentially
You might also need terminators to avoid reflections.
Yes, you probably need to know the drives optopcoupler input circuitry
Many Chinese drives get this wrong (no reverse polarity protection diode
across OPTO LED) In this case, an external reverse diode/resistor pair would
handle the reverse direction oveshoot and prevent OPTO damage in the OPTO LED
off direction
Many drives have 220 ohm series resistors, this would result in less than 50%
overshoot (for say 750 ns with 150 meters ) which should not be harmfull in
the on direction
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Mesa Electronics
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