and maybe sometimes the signal wire is quickly disconnected, or any other wire powering the sensor or the tachometer, an then the crazy measurements happen. I think that the micro-vibration of the lathe may interfere with the electric connections. I then mounted the 2N7000 soldered directly to the wires, instead of using jumper wires and it seems to have solved the problem. I have a couple os tiny pcb voltage regulators, so I used one to get 5V to power the hall sensor, instead of using 12V. I tried with the diode method and it worked worst. Would it happen because the 2n7000 get´s lost in the switch-on-off-on-off so fast? Or it´s because I didn´t connect it yet to the gecko? If I connect the tachometer´s input to the Drain, the Hall Sensor output to the Gate (and has also a wire from the gate to an unconnected Gecko 540 input yet), and the Source to the GND, the readings are ok until close to 1200 RPM. If I connect the output of my Hall Sensor (it has a 1K resistor between the Vin and Out) directly to the Tachometer´s input, not using for now the 2n7000 just for testing purposes, the measurements are correct through all the variations, from 0 to max, with no ripples, no crazy readings. It goes to 2000 RPM, 3000 RPM, gets back to 1000 RPM. When I put my lathe to it´s max RPM (Close to 1680 RPM), the tachometer gets crazy. When testing the RPM using the Hall Sensor - 2N7000 - Tachometer module, I get stable results from 0 RPM to 1200 RPM more or less.
the only thing I haven´t done right now is connecting it to the Gecko G540 yet. Hall sensor installed on the spindle, everything set-up.
I´ve done all modifications inside my lathe, and it´s new control box. Hi John! It´s some months since our last posts!! I´ve been busy with work, so couldn´t test it all over my lathe. You can use a multimeter set to mA to measure the current from the G540 input to groundĪnd the current from the tachometer input and ground to verify the current is what I expect Hall switch and tachometer without connecting the switch output, G540 input or tachometer together That 6.5 mA under the Hall switches limit The total the Hall switch has to sink will be 18.5 mA (you will probably find it less than 1.6mA but I can find any data for the module ) The current that will flow to ground will be 1.6mA
Gecko g540 outputs series#
If the tachometer input is like the standard TTL 7400 series logic IC When you ground the input pin the current = 11V /2K2 = 5mA If you assume the volt drop across the LED in the G540's input opto-isolator is 1V The current through the 1K resistor will be 12mA If your running a Taig mill this may be over kill, if your running a large router it might make more sense.With the switch output low it has to sink the current from the G540 input, 1K pullup resistor and the tachometer input These as basically really fancy contactors that have been designed and tested so they work with a very high degree of certainty. NOTE: technically speaking a 'safety' type contactor should be used, sometimes called an MCR. For small machines you may find that the 'breaking' current rating of an EStop switch is adequate to interrupt power to the power supply, for larger machines you will need to use a contactor. This is done by removing the input power from the drive power supply (typically) by use of a contactor. In industrial machines when you hit EStop all drive power is removed from the things that move. Re: Mach3 Setup for Gecko g540 & PriceCNC AVHC10 THC Post by The-Meerkat Mon 4:27 am Attached is a more detailed look at the pins for a 12 pin Gecko 540 and the Price CNC AVHC 10 Torch Height Control. This way the VFD/spindle will only have power when Mach is out of Reset mode and you still have an isoalted start/run for the VFD.ĮSTOP - Neither the EStop input on the G540 or the any output from Mach3 make up a 'real' EStop. For VFD's I usually use output 1 of the G540 to power a relay/contactor to apply power to the VFD and output 2 to drive a small relay to start/run the VFD. The G540 will also not turn on the relay unless you tell it too. For security reasons i really wan't the mach3 to do disable the gecko when i hit the reset and enable when i hit it again.įor the VFD issue - use the Mach output to drive a small relay, use the relay to send the enable signal to your VFD. If i press the big reset button in mach the gecko does not disable!? So if i press my emergency stop and release again, the gecko just enables without me having to reset it in mach3.
But when i turn of the system, the VFD will start to spin for a second until the capacitors in it has discharged. I can off course always turn the gecko on with the VFD and there is no problem. The resistance between 0V and the output is to low to not enable the output when the gecko is without power. but if i turn on the gecko the output goes to off unless i enable it in mach3. The problem is that if the gecko is off the output goes on. I use one of the outputs to set my VFD drive in run mode and start the spindle.