On 12/6/24 06:56, Leonardo Marsaglia wrote:
Hi Gene! How are you?
Leonardo, If looking for a bunch of encoders, Peter may be able to build
a 7i90HD file to order. It has 72 i/o pins. So there's buckets of i/o.
With 4 encoders, I'm using 3 of them on the Sheldon, One for the
spindle, and two replace the cranks on the apron that allow me to drive
it by hand. The dis is the cost as it needs 3 7i42TA's to guard its
gpio pins from over 3.5 volts of logic. The config I'm using has 4
encoders stock. It can be used with a parport breakout, or with a 3 wire
spi interface at quite blazing data speeds (42 megabaud writes, 25
Megabaud reads) with an rpi4b clone doing the work.
That is in 32 bit packets going both ways.
Do you mean 7i42TA?
Yes, mental typu there. fixed in echo above.
that's probably another option. I only need to read
frequency so I don't need quadrature or direction, so as Peter says I'll
have more pins available.
That simplify's things greatly then, any gpio can be hooked to a counter
to measure frequency per period, with something in hal setting the
period. Piece of cake. Several flavors available.
Speed of counters in the pi clone might be a problem. I've found the
encoders in a 5i25 can track a 1k ppr encoder on the spindle motors back
shaft. but the 7i90HD would need that counter in its firmware to keep
up. My problem in the original rp3b wasn't the encoder speed, but the
lathes ability to track the 100 ppr encoder dials, so I added a third
execution loop, running at 200 HZ just for my manual control stuff. I
can still spin a knob faster than it can move but it catches up in a
fraction of a second. The rpi4 in there now may do the same but its not
detectable as a general rule. And has no effect on gcode speed. That pi
and monitor are never turned off, it controls all power to the lathe
with the F2 button driving SSR's.. pi and monitor are 22 watts. pi
uptimes are from maintenance session to maintenance session as I have a
tiny ups on it, and a autostart kohler 20kw in the back yard. Originally
installed for the wife's COPD, but she passed 4 years ago tomorrow.
Hope you're doing great!
Not to bad for a 90 yo diabetic, fixing to get some stents put in my
legs as soon as they get a cat scan to find where the others are. Take
care yourself Leonardo.
El mié, 4 dic 2024 a las 11:34, gene heskett (<ghesk...@shentel.net>)
escribió:
On 12/4/24 06:21, Leonardo Marsaglia wrote:
Hi Andy,
7i89?
Not as many encoders, because there are not as many pins...
Leonardo, If looking for a bunch of encoders, Peter may be able to build
a 7i90HD file to order. It has 72 i/o pins. So there's buckets of i/o.
With 4 encoders, I'm using 3 of them on the Sheldon, One for the
spindle, and two replace the cranks on the apron that allow me to drive
it by hand. The dis is the cost as it needs 3 7i44TA's to guard its
gpio pins from over 3.5 volts of logic. The config I'm using has 4
encoders stock. It can be used with a parport breakout, or with a 3 wire
spi interface at quite blazing data speeds (42 megabaud writes, 25
Megabaud reads) with an rpi4b clone doing the work.
Had I built my 1940's Sheldon 11x54 first, I would never have used
anything else in my other 3 cnc'd machines. The other 3 were done first,
are run by big old Dells, with a 5i25 in the Dell and a 7i76D plus a
parport breakout, usually with the opto-isolators bypassed for speed.
That 5i25 encoder is watching a 1000 ppr encoder on the rear of the 1hp
motor on my GO704, rated for 1800 rpm but has not dropped a bit ever
once the opto's in the parport were bypassed. That 90 volt motor with my
124 volt psu can do 21,000 rpms wide open. I'm amazed I haven't blown
the nylon gears in the heads gear-shift. I've been abusing it that way
since 2009. And still on the same factory brushes. I have i/o enough
left on that Sheldon build to run an Emco tool changer if I ever find
one I can afford.
Yeah, that seems like another option.
El mar, 3 dic 2024 a las 22:52, andy pugh (<bodge...@gmail.com>)
escribió:
On Tue, 3 Dec 2024 at 15:32, Leonardo Marsaglia <ldmarsag...@gmail.com>
wrote:
The main concern to decide my configuration is: Is there a 7i53 like
board
that uses the SERIAL I/O interface instead of the 50 pin connector?
7i89?
Not as many encoders, because there are not as many pins...[...]
Cheers, Gene Heskett, CET.
--
"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
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_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
Cheers, Gene Heskett, CET.
--
"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
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
