Will Acorn work on my little VMC

All things related to the Centroid Acorn CNC Controller

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craigc
Posts: 22
Joined: Sun Sep 12, 2021 12:34 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No

Re: Will Acorn work on my little VMC

Post by craigc »

The spindle servo motor and drive have a resolver connected, the servo drive has a Encoder out DB9.
from the manual
Resolver

4.1.3 Resolver feedback - X8
The resolver connections are made using the 9-pin D-type male connector X8. Twisted pair
cables must be used for the complementary signal pairs e.g. SIN+ and SIN-. The overall
cable shield (screen) must be connected to the metallic shell of the D-type connector. The
resolver input is used to create an encoder signal inside the MicroFlex. This provides the
MicroFlex with an equivalent resolution of 4096 pulses per revolution (ppr), although this can
be reconfigured in the Mint WorkBench Commissioning Wizard to provide 1024 ppr. The
MicroFlex provides an input accuracy of ±3 counts. When used with a typical Baldor BSM
series resolver motor the combined accuracy is ±11 counts (calculated with the input
equivalent resolution set to the factory preset value of 4096 ppr). The left LED illuminates red
if there is a fault or loss of the resolver signal; the right LED is unused.

Connector X7 encoder output

4.1.4 Encoder output - X7
This output can be used for position feedback to a motion controller. It is recommended that
this output only drives one output circuit load. The encoder outputs are differential and
conform to the RS422 electrical specification. Shielded twisted pair cable is recommended.

If the MicroFlex has resolver feedback, a simulated encoder output is produced at X7. If the
resolver input has been configured to simulate an encoder input of 1024 pulses per
revolution (ppr), the output at X7 can be set to either 512 or 1024 ppr. If the resolver input
has been configured to simulate an encoder input of 4096 ppr, output modes of 512, 1024,
2048 and 4096 ppr are possible. Note that these values represent actual encoder lines, not
quadrature counts. The simulated encoder output is in the same direction as the resolver
input. See the keyword ENCODERLINESOUT in the Mint help file.
Location Connector X7
Pin Name
1 CHA+
2 CHB+
3 CHZ+
4 (NC)
5 DGND
6 CHA-
7 CHB-
8 CHZ-
9 (NC)
Description Encoder output on a 9-pin female D-type connector

The spindle motor is not 1:1 but rather 1:2, the big pulley is on the servo motor and the small pulley is on the spindle. I've read on this forum that will work where as 2:1 will not work. Hope that's true.
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