G540 ins & outs

[riche543]

Quick question on a gecko 540 are there enough input/output pins for : superpid spindle control / hall effect limit/home switches With leds. & a tool probe .
Cheers

Riche

[Mariss Freimanis]

The G540 uses every I/O line the parallel-port offers. Besides the 4-axis high-speed STP/DIR lines, there are the secondary auxiliary I/O lines. One output is used for the 'charge-pump' (better called 'watchdog timer'), another AUX output is used for the 50Hz PWM 'VFD drive' optoisolated analog voltage output, an AUX input is used for an E-STOP input while another AUX input is dedicated for a FAULT input to MACH3.

When all is said and done, this leaves 4 uncommitted inputs (the 4 G540 general purpose inputs) and 2 uncommitted outputs (the 2 G540 outputs). This uses up the parallel port completely.

Mariss

[riche543]

Thanks for all that info mariss
Much appreciated
Cheers.

Riche.

[Majorstrain]

Hi Richie,
I've done exactly what you are trying to implement.
I have 6 hall effects limits in parallel on 1 input although this needed a current limit resister in the signal line. Then I have each home probe hall effect on a separate input. The touch is connected in parallel with my Z home input. All have leds at the hall effect location. The two outputs I use for driving step and direction on a G203.
Cheers,
Phil.

Edit.
I should say that I needed the current limit resistor because I run the hall effects off a 5volt supply.

[riche543]

Thanks Phil

Where would the current limiter go , bit of a noob when it comes too electrics
Cheers
Riche

[Majorstrain]

Thanks Phil

Where would the current limiter go , bit of a noob when it comes too electrics
Cheers
Riche

Hi Riche,
I'm out at the moment and using the phone to post. Bloody phone! That was the reason for the double post. :-)
I'll draw up a diagram when I get home and get it posted tomorrow some time.
Cheers,
Phil

[riche543]

Much appreciated phil, doesnt have to be to flashy,
Still currently building 2nd cnc ,just gathering all info i might need to , when i get stuck. I know what ya mean bout phones i have iphone not too bad but i got big fingers so quite often press send or delete before finished .. lol.
Cheers
Riche

[Majorstrain]

Hi Riche,
Here is the wiring diagram for the hall effect limits wired into the G540.
Wiring diagram

Click on it to go to the image on my Photobucket page.

I have a separate 5 volt supply that is powered from the 50volt supply to my G540. The ground from the 5 volts and the 50 volts are connected together.
For the 5volts I pulled apart a 5volt dc switch mode (ie not a transformer type) wall wart (plug pack here in Aus) and removed all the components from the input pins up to and including the the bridge rectifier. The 50V dc is wired into the + and - holes where the rectifier used to be.
Most plug packs will work on 50V dc if they were a 110/220V ac type.

The LED's were blue surface mount just because the blue is quite bright and with the surface mount gear I could solder them directly to the hall effect.
none of the resistors or led's connect to the ground line. It may look like it in the photos below but they don't touch.
The LED is off until the magnet actuates the hall effect. The signal into the G540 is idle high and active low.

Hall Effects Epoxied to the table




Magnet holder


Overview


Without the 4k7 resister inline with the six limits there was enough current leakage to have that input triggered all the time. The 4k7 value was a trial and error thing. Not enough and the input was triggered, too much and it would not trigger when the magnet enabled the hall effect.

My touch probe for setting the tool zero height works just like a switch being closed. (completed circuit though the touch plate , mill frame and cutter)
so that is the only thing that has a signal to ground wiring connection.

My hall effects are just epoxied to the table and the magnet is mounted in a holder. The hall effects are the non latching kind but like most they are magnet polarity sensitive. (doesn't trigger if the magnet is the wrong way around).

I don't have a problem with ferrous swarf sticking on the magnet because my tooling plate is longer and wider than the original table to which it is bolted.

X3 Mill with 4th axis, tooling plate and 24k rpm spindle



The paper covering the tooling plate is just baking paper held in place with magnets around the edge. It keeps all the crap out of the holes not being used and the alignment pegs and hold down bolts just push through the locations you need. After each setup you just replace it with a new sheet.

Hope this helps.
Cheers,
Phil