On 2/27/23 14:02, John Dammeyer wrote:
Two problems.
One: $249US and two: out of stock at the moment.
When I did my lathe, there was the 7i90HD but at $65, it has no
protection for the fpga, its connected directly to the outputs. And I
learned 2 things.
1. 7i42TA's were needed between the 50 pin i/o connectors and the real
world to protect the fpga from noise or even the normal 5 volts. 3 of
those did the trick, but were about $130 added to the original $65,
which I blew 3 of learning about #2
2. Single bolt grounding. Meaning ANYTHING grounded, is grounded by
stacking its ground wires up on this single bolt. No other grounds
allowed. This includes the third pin wire from the line cords static ground.
Without item 2 I had noise on everything reaching beyond the 100 Mhz
bandwidth of my scope at the time, and peaking at over 100 volts peak to
peak. No wonder I blew 3 cards.
With it rebuilt to satisfy #2, the measured noise dropped to about 200
MILLIVOLTS! That 3rd card is still in it, I just moved the blown
circuits to another port.
The 7C80 sounds like all that, could do everything I'm doing with a
7i90HD and 3 7i42TA's plus a spinx1 to control my vfd. With the general
rise in costs since 6 years back, $249 seems like a good deal. And I
have about 30 i/o left over, way more than enough to run a tool changer
like an emco. But I'm not actively looking for one.
Mind you, so is the 7i92H but it was around $89 and with two Chinese BoBs at $5
each comes in much cheaper.
So then the question is both require waiting. A Pi4 isn't cheap either nor in
stock.
This I haven't tried to run LCNC on, but I bought a 4 pack of banana pi
m5's with even more speed than the pi's, for $170, and they are running
octoprint, one per printer in my printer farm just fine and as stable as
my pi has been. One could probably recompile rpspi.ko to address the
gpio used and it might be as simple as that. That same fix would likely
make an orangepi work also since it uses the same broadcom gpio core as
all the new "pi's".. The voron printers use a can bus to run the hot end
running klipper to run the big voron's from an orange pi.
Food for thought. If Peter can supply the 7C80's in a reasonable time
frame. Peter?
And an ACORN CNC kit is $329. Looks like in stock.
https://www.centroidcnc.com/centroid_diy/acorn_cnc_controller.html
It's hard to convince someone to go the CNC route with LinuxCNC when all they
want is simple 3 or 4 axis with none of the other amazing features that
LinuxCNC offers.
John
-----Original Message-----
From: andy pugh [mailto:bodge...@gmail.com]
Sent: February-27-23 10:32 AM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Linux CNC on Pi3
On Mon, 27 Feb 2023 at 18:15, John Dammeyer <jo...@autoartisans.com> wrote:
Ah. I forgot about that little tidbit.
SPI (Such as 7C80) ought to work though.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
� George Fitch, Atlanta Constitution Newspaper, 1912
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Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>
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