Acorn serial or Modbus via host PC USB port

All things related to the Centroid Acorn CNC Controller

Moderator: cnckeith

union7
Posts: 7
Joined: Sat Sep 23, 2017 5:50 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC11: No
CPU10 or CPU7: No

Re: Acorn serial or Modbus via host PC USB port

Post by union7 »

Keith already advised that no serial comms are available for user/g code use, but that he would try to suggest methods that use the Acorn board's i/o hardware, in lieu of serial.


Serial would not necessarily need to be done via the control board it could (theoretically) be done directly from the PC software using the PC's USB...that is how Mach3 does it. For example one USB port is used to talk to my chinese motion controller board and an entirely separate USB port can output general purpose serial. I happen to use it with a D sub RS232/USB cable, but RS485 converters can be implemented as well.
I can't speak for Centroid, but maybe someday they will add ability to use serial comms within Macros to their software...since it would not require any board revisions.
AcornFanBoy
Posts: 13
Joined: Sun Feb 18, 2018 3:42 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: E8EB112A1F7F-0312180719
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Finland

Re: Acorn serial or Modbus via host PC USB port

Post by AcornFanBoy »

cnckeith wrote: Mon Oct 02, 2017 1:54 pm photos of the turret please.
photos of machine as well. photos are worth a thousand words!

how many inputs and outputs does the TURRET need to operate?

fyi..there are beta testers running basic lathe auto turrets with Acorn as is.

and it would be helpful if i knew the type of turret (electric reversing motor i presume?, please advice) and how many input and outputs it requires to operate.
Hi cnckeith,

I was also searching for information whether Acorn has any serial communications capabilities to interface micro controllers such as Arduino.

I have an Emco Compact 5 CNC lathe, and I want to retrofit it with Acorn. I don't have Acorn yet, but I've been reading the forums and documentations a lot, and almost everything looks simple: Z and X asis are normal steppers, and I will likely interface them via Gecko G540, and spindle control will be done using the 1-10V interface to KBIC-240 and KBSI-240D as the main motor is a 180VDC permanent magnet.

What I haven't been able to figure out is how to control the tool turret. Emco C5 has a turret where a DC motor turns forward for a predefined time with full voltage, and then it reverses direction, lowers the voltage and locks the toolpost by stalling the motor against a ratchet. The DC motor is powered on all the time while it's holding the position, the motor has been designed to handle it.

Voltage over motor during forward movement is 13.9V, during reverse -4.2V, and during stall -3.2V.

My turret has 6 positions, and there is no feedback, i.e. CNC doesn't know which tool is selected. User can only tell the turret to forward 1...n steps at a time.

In the Acorn conversion I could add a sensor so that we would know the turret position.

Other people have done the conversion using arduino + simple DC motor control circuits. User tells arduino via RS-232 which toolpost number to move to, and the arduino does the rest. When the turret has moved to a correct position, a message is returned via RS-232.

Keith, you mentioned that during the beta testing phase users were able to control their turrets with Acorn as is. Do you have ideas how I could control my turret in the scenario I described?

I'm sure you're familiar with this simple turret design, but here are a few pictures of it.

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Last edited by AcornFanBoy on Mon Feb 19, 2018 4:29 pm, edited 3 times in total.
union7
Posts: 7
Joined: Sat Sep 23, 2017 5:50 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC11: No
CPU10 or CPU7: No

Re: Acorn serial or Modbus via host PC USB port

Post by union7 »

I have also heard that Acorn will offer Modbus in the summer of 2018....ask about this. It's the only reason I did not go with it.
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