Custom-made controller based on Gecko G540

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Jacek
Berichten: 2
Lid geworden op: 18 nov 2020 17:20
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Custom-made controller based on Gecko G540

Bericht door Jacek »

Hello everyone!

I would like to show off with my custom-made CNC controller and subject it to your criticism. It is based on Gecko G540 module and purposed for driving a 3-axis milling machine with moving table or gantry, or other similar machines. Here is the specification:


Gallerij Link

Driver for motors: Geckodrive - Gecko G540
- 4-axis driver for 3,5 A max bipolar steppers
- integrated peripherals driver
- microstepping (10-step)

PC interface: Warp9 Tech Design - Ethernet SmoothStepper (no LPT port needed, communication through ethernet)
- eliminated problems with LPT and Windows "timing" issues
- huge possibilities for system upgrade (two spare LPT-alike ports left)

Computer: old and used Lenovo 3000 C200 laptop
- WInXP SP2 & Mach3 + plugins & SmoothStepper

Bipolar stepper motors (3 motors, 4th one possible):
- Type: NEMA23 - R57BYGH4331 (200 steps/rev)
- Current/Phase: 3,5 A max
- Motor shaft: 1/4"

Power supplies:
- 48 V - 7,0 A (for Gecko driver motors)
- 12 V - 1,3 A (for fans and relays)
- 5 V - 3,0 A (for SmoothStepper)
- dedicated laptop power supply
- all voltages available on DIN rail connectors

2 relay blocks (for spindle, coolant etc.):
- every block is a 3PDT relay (TE Connectivity - PT370012) in DIN rail module, with flyback diode
- max 400 V AC - for 250 V AC max 10 A
--- "PC type" IN and OUT slots on panel (by-pass, fused)
- max 300 V DC - for 30 V DC max 5 A
--- "microphone type" IN and OUT slots on panel (by-pass, two poles)

Input and output connectors:
- 6 NC type "limit" switches: X++, X--, Y++, Y--, Z++, Z--
--- connected in series, "MIC type" connectors on panel
- 3 NC type "home" switches: X home, Y home, Z home
--- connected in series, "MIC type" connectors on panel
- 2 NO type digital inputs (for tool length probe etc.)
- 1 analog output 0-10 V (PWM for VFD spindle)

Other:
- mains switch with fuse, E-STOP button
- 4 fans (connected by WAGO quick connectors)
- cables organized on DIN rail WAGO connectors for easy maintenance and modification

Mechanics:
- structural aluminum profiles enclosure frame
- 2mm powder coated steel walls, fixed in profile seals
- stainless steel mounting plate
- easy access to internals without tools
- detachable transportation handles (can be used as standoffs when used vertically)
- dimensions (without handles and connectors): 540 mm x 400 mm x 135 mm
- weight (without laptop and motors): approximately 16 kg


Gallerij Link

Gallerij Link

Gallerij Link

Gallerij Link

PS. I was doing this project a couple of years ago in my home country Poland as a hobbyist and in the end I successfully sold it to someone, who was willing to retrofit his machine. Nowadays I have in mind something more "industrial", based on touchscreen industrial PC.
Jacek Tylenda - Ik hou van CNC-machines!
hfjbuis
Berichten: 979
Lid geworden op: 13 feb 2017 00:26
Locatie: Hoensbroek

Re: Custom-made controller based on Gecko G540

Bericht door hfjbuis »

subject it to your criticism
Your setup is based on Windows XP. Doing so, you created a predictable problem not be able to get Windows XP running on newer hardware when this PC is end of life. Solve this and you have a maintainable system that has a future.

I can see that the wiring is very decent but not if you mixed low voltage control signals and "high current/voltage" signals. If you mixed these signals, this could lead to an unstable system.

According to (European) safety regulations, you should use an earth wire on every metal panel. If the surface of the panel does not have a good electrically conduction (painted or aluminum), you should use a toothed washer between the panel and the earth wire.
I see no earth earth wire on the bottom panel.

I see 4 fans, that is probably a noisy overkill for switching power supplies. One in and one out should be enough!

You don't use ferrules at the end of all your wires, you should use a ferrule on all non solid wire ends to avoid shorts.

You can shorten that flat cable!

The Ethernet connection is a cable through the front panel without a protection sleeve!. Replace it by an Ethernet socket!!!!
There is a black cabel through the front panel without a protection sleeve. Use a socket!!!!

In general a laptop is not advised when running Mach3.

Overall you did a very good job!
Jacek
Berichten: 2
Lid geworden op: 18 nov 2020 17:20
Contacteer:

Re: Custom-made controller based on Gecko G540

Bericht door Jacek »

Thanks for this honest opinions! I really appreciate this input :-)

A couple of remarks:
- You can still run Mach3 on more "modern" OS versions or switch to Mach4, however Mach4 does not receive very positive feedback. I finished this project in 2017. BTW. I tested this system with this laptop and it was running smooth, with no lags, etc. which was common during the LPT times. Ethernet SmoothStepper serves this job well.
- I know the rules regarding the signal routing and tried to do my best to separate power, control and freq. signals as much as possible.
- With regards to earthing: all external panels have "PE" wire screwed with a toothed washer, "fixture plate" does not have one - green terminals have a tooth that bites into the DIN rail. What's more - I measured it :-)
- With fans you are right - it is hell of a noise! Same for ferrules and protection sleeves, it was just for cost saving sake.

I learned a lot when building this one and especially from the comments I received from Polish CNC community. Thanks for yours as well!
Jacek Tylenda - Ik hou van CNC-machines!
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