New DIY CNC with MACH4 ESS/MB3 and clearpath servo

I am slowly inching forward in building my first cnc.

I'm using ESS/MB3 combo with clearpath CPM-SDSK-3421S-RLS motors.

I am almost finished installing hard stops. I have temporarily wired all motors to the board, and tuned all motors with clearpath software. I have also calibrated the distance in motors so one inch in mach4 is 1 inch on the table.

What I would like to do primarily is repeated jobs (G54), so my question is;

How do I set up and wire the limit switches, home switches, and Estop?

I am assuming I need 6 limit switches and 3 homing switches. 2 switches per axis for limit and 1 per axis for home. Should estop be wired directly to the MB3 board or wired with limit switches?
How do I wire HLFB + and - from motors for homing?

I was going to use these switches for limit and homing, Is this ok?

https://www.amazon.com/HiLetgo-ME-81...8P2NYTMZ9YP7B7

What is the best way to go about this? Electronics and electrical schematic is not my thing so I'm struggling reading and understanding ESS and MB3 manuals

A short video of machine working.

https://www.youtube.com/watch?v=zRLg...ature=youtu.be

Appreciate any help I can get to get this going!

Darko

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Originally Posted by Darko

What I would like to do primarily is repeated jobs (G54), so my question is;

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I'll start with this comment first just to make sure you understand how offsets work because it's important to know.

G54 as nothing to do with repeating work it's just a WORK OFFSET coordinate referenced from MACHINE coordinates.
You can have multiple WORK OFFSETS ie: G54, G55, G56 setup on you table at the same time. Each one will have it's own WORK ZERO which is a known distance from MACHINE ZERO coordinates. These are called FIXTURES and often get called FIXTURE OFFSETS.
G54 is usually the default FIXTURE OFFSET the controller starts up in and most people never change it or even know about it so just cut in G54 all the time, whether that be a single part or 10,000 parts, they all get cut in G54 OFFSET.

However, OFFSETS allow you to cut several jobs with different thickness materials around the table with one G-code file, or as is often the case if cutting on both sides of a part is required you can combine a 1st and 2nd OP in G-code file. So after the 1st OP on first part is finished then you can layout the 2nd parts 1st OP and the 1st parts 2nd OP on the bed at different loactions using G54, G55 OFFSETS and they will be cut together.
Using Fixtures is a very efficeint way of using the bed if making multiple parts. BUT G54 as nothing to do with repeated cuts.!

Quote:

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Originally Posted by Darko

How do I set up and wire the limit switches, home switches, and Estop?

I am assuming I need 6 limit switches and 3 homing switches. 2 switches per axis for limit and 1 per axis for home. Should estop be wired directly to the MB3 board or wired with limit switches?

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Ok well you have options here.?
You can have a Fixed limit Switch at each end and a Separate Home switch as you describe or you can 1 Limit which travels with the axis and senses or Hits a target at each end of travel. The advantage to this is less switches and less wiring.
You can also configure the Switch so it does both HOME and LIMIT duties which removes another switch and 1 less input required, however this does come with a slight safety disadvantage.? When the machine is doing the HOMING sequence the LIMITS will be disabled so it's not quite as safe than if you had a separate HOME switch.
I find in practise that it's perfectly safe because when homing your traveling very slowly and can see if something as gone wrong and it's not stopping before it gets to the limits.

The E-stop is a completely different ball game if you want a truely Safe setup. The E-stop should kill all movement and remove Power to the main Drives, then it should inform the Controller ie: Mach4 this as happened.
This is known as a hard wired E-stop which physicly removes any chance of movement using relays or contactors rather than relying on Software to make the System Safe, which it can never do.
It should also be designed so the E-stop (and possibly limts) are part of a latching Circuit so when E-stop is hit the sytem can not be reset and power turned back on on by just releasing the E-stop button, To reset a further Momentery Reset button shoud be incorprated which needs to be pushed to latch the circuit and if the Circuit isn't safe ie: E-stop or limit still pressed or any other safety built in to the circuit then the circuit won't Reset (latch).

This isn't as difficult to do as you may first be thinking as it's only a few relays or contactors and a Momentery Button extra, which are then wired in a certain way to provide a latching circuit.
The advantage is that it's very safe and can easily be upgraded at later date to add more safety ie: lets say you fit a ATC spindle which requires air, you can fit a pressure transducer into the system so if it senses NO air it won't allow a Reset.

Regards where to wire on the MB3 then the Limit signals and the E-stop signal just go to any spare Inputs, you then just configure Mach4 to watch that Input #.
But the actual safety is handled by the Hard wired circuit, the circuit then just sends a signal to the MB3 to inform that's it's happened and whether it's cleared or not.

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Originally Posted by Darko

How do I wire HLFB + and - from motors for homing?

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I'm presuming this is the INDEX Pulse on the encoder that the drive can output when it's homed. This I'm not sure about as I've never used these drives and I don't use Mach4 so can't help regards setting this up.
But usually you will set the controller up so that it uses HOME ON INDEX feature and feeds the INDEX output from the drive into an INPUT on the MB3, the controller then watches this INPUT when homing rather than using the HOME Switch as it's much more accurate.
A physical HOME switch is often set just before the home location as a marker. The controller will then send a signal when it see's this switch trip to the drives HOME INPUT using an OUTPUT on the MB3 which then sets the drive looking for the INDEX pulse. When the drive finds the INDEX pulse it then sends the signal back to the controller.

Hope this helps.

I know it’s a wooden machine but you have done a really nice job on the build. All the essential bits are there and you have grasped the principles of what is required.
ClearPaths are good but regular steppers would have done the job as well, but you are there now.

Full marks to Dean who has again gone out of his way to give a full description (or is a super fast typist!)

On my YouTube channel Ep26 of the CNC series shows an overview of the control box which might be interesting. Electronics always looks complicated when it’s all up and together but it is doing what Dean described above.

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Originally Posted by routercnc

Full marks to Dean who has again gone out of his way to give a full description (or is a super fast typist!)

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I'm no typist but I've had plenty of practise so it's not exactly going far out of my way.

Thank you very much for your reply, and help I know I haven't replied in a while but I've been busy with work. I have been reading in trying to learn about building CNC machines. I'm hoping on the long run once I'm finished with this and complete everything, eventually, I want to transfer all the hardware and build the steel machine.

I am making progress on my machine and I have made some updates I think for now the only thing left is the control box and what are the essential things that I should have in there.

http://www.mycncuk.com/threads/14295...753#post122753

Thanks!

Darko

Hi,

I'm an engineer with Teknic and I came across your post regarding wiring ClearPath's HLFB and homing options.

When configuring a ClearPath using the MSP software you'll notice options for High Level Feedback (HLFB) to your controller. While there are a variety different feedback options ClearPath can present to the controller, for machines like yours, designers often select "ASG-P" (All Systems Go - Position) option. With the HLFB configured for All Systems Go - Position the ClearPath will assert (turn on) the output when the servo is enabled, homed or at commanded position and de-assert (turn off) when the servo is in motion or if the motor's position is outside of your desired accuracy range.

Once the desired feedback functionality is set in the ClearPath, you just have to configure your controller's input to correctly read and interpret the HLFB signals. There is information regarding wiring the ClearPath HLFB output to different types of controller inputs as well as descriptions of all the High Level Feedback functional options in the manual, located here: https://www.teknic.com/files/downloa...ser_manual.pdf

Regarding homing, there are a variety of mechanisms to home a machine. As an alternative to sensor-based homing, you may consider homing to a hard stop using the ClearPath's Precision Hard Stop Homing algorithm. This homing method reduces wiring complexity and provides a more repeatable and precise home position. Here's a video segment that shows the functionality and set up for Precision Hard Stop Homing: https://youtu.be/-LubKmpB5-8?t=214
If you have any other questions, please contact us at 585-784-7454 or https://www.teknic.com/contact/