I have used an RS232-to-RS485 adapter and just plugged it into the PC
serial port. It was not ideal to add another cable from the PC but it
works fine. There are MODBUS drivers for LinuxCNC.
Danny
On 4/11/2019 5:30 PM, Peter C. Wallace wrote:
On Thu, 11 Apr 2019, Gene Heskett wrote:
Date: Thu, 11 Apr 2019 17:56:45 -0400
From: Gene Heskett <ghesk...@shentel.net>
Reply-To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
Subject: [Emc-users] For PCW
Greetings Peter;
The new vfd materialized here today, and I see it actually has what it
calls an RS485 interface, a teeny little white 3 pin socket on its
motherboard.
And I have one or two 422 to 485 translators, the $2 variety, that I
believe are duplex capable as I had to wire them to a solid logic level
on the 5i25 end of them before they would take the balanced signals from
the encoder I put on the spindle motor of my G0704, and make nice 5 volt
rail to rail square waves to feed the 5i25.
If I jury rig the separate 422 lines end of that to the 422 terminals on
that 7i76D, can I talk to a huan yueng lookalike? That is what I
supposedly bought but the instruction booklet makes no brand claims.
It is a YL-620-A, and it also has the usual analog interface too.
It claims no ascii, but supports the modbus RTU protocol, and mentions
modbus several times.. Am I better off useing the analog, or is the
RS-485 the better control?
Unfortunately you cannot do this currently since MODBUS is not
supported by the Hostmot2 UART driver
Analog control may be better for things like rigid tapping since the
normal MODBUS driver is a userland task (and I'm not sure how real
time the MODBUS implementation in the VFD is.
I also see an AO output, but its reads like 0-5 volts, which doesn't
sound like it would work to indicate the achieved speed via one of the
A/D's on the 7i76D when the 7i76 goes to about 38 volts full scale.
If you have a spindle encoder, that a better way to get speed feedback
This is the first vfd I've had that actually has braking R terminals,
and
says optional, but if used s/b 100 ohms, 100 watt. What advantage would
hooking one of those up amount to?
Fater slow-down and faster reversals if tapping (better control of depth)
Thanks for any advice Peter.
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)
Genes Web page <http://geneslinuxbox.net:6309/gene>
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Mesa Electronics
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