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Messages - MN300

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11
Mach4 General Discussion / Re: Servo Wiring
« on: May 20, 2022, 08:45:22 AM »
There is a risk to the opto-isolators created by paralleling inputs powered by different 24V supplies. If one supply is off its opto-isolators will receive a reverse bias from the other supply. Their cathodes will see about 22V or 23V from the shared signal line ( 24V minus the emitter drop of the other optos) while the anodes will be at zero volts ( the unpowered 24V rail).
The maximum reverse rating of the typical opto-isolator is about 5 volts. In the real world the maximum is usually far higher than the spec but applying 4 times the rating is a risk.

13
General Mach Discussion / Re: Touch Probe Wiring Question
« on: March 27, 2022, 10:21:05 AM »
Hello, the wiring diagram on the probe website is unusually well commented. It shows a simplified version of the probe's output circuit. Not shown are the mechanical sensing switch or the LEDs but the text describes their action.
The diagram shows a 10K pull up resistor and a switch which represents the output of the NPN transistor. When the probe tip is displaced the transistor connects the yellow signal wire to ground. Electrically this is like the old probe tip touching a grounded metal part.

All connections are made to the interface board.
Black wire to the GND terminal
Red wire to the +5V terminal
Yellow wire to input 4 terminal (probe input)

14
Mach4 General Discussion / Re: Slave Y axis getting behind in time.
« on: March 24, 2022, 11:14:09 AM »
My comment was based on Craig's mention that the slave motor typically turns in opposite direction as the master. He suggested if that was accomplished by changing the polarity of the direction signal to the slave motor the number of pulses received by one of the motors could be off by one when the direction reverses.
I suggested reversing the slave motor by interchanging the wires to one of the stepper windings so the polarity of the direction signals could be the same.

You mention the fault occurs over ten days. If you turn off power or disable the drives the stepper motors can align themselves to the nearest pole causing a slight position change. Are you re-zeroing every time power is restored? More explanation of what you are doing would help.

15
Mach4 General Discussion / Re: Slave Y axis getting behind in time.
« on: March 23, 2022, 08:17:23 AM »
Quote
Typically a slave motor turns in the opposite direction to the master motor. Thus if the Master is in FWD the slave will be in REV.

If you reverse one of the windings of the slave stepper it can be fed with the same polarity signals as the master. That should make the two motors behave the same.

16
PoKeys / Re: NPN proximity sensors 24v supply & pokeys 57
« on: March 12, 2022, 04:24:32 PM »
The EE SX671 may not be suitable for your CNC use.

ee-sx47_67_ds_e_13_2_csm483.pdf
The datasheet , page 5 says;

"These Photomicrosensors have an IP50 (conforms to IEC) enclosure
and do not have a water-proof or dust-proof structure. Therefore, do
not use them in applications in which the sensor will be subjected to
splashes from water, oil, or any other liquid. Liquid entering the
Sensor may result in malfunction."

17
PoKeys / Re: NPN proximity sensors 24v supply & pokeys 57
« on: March 02, 2022, 07:44:11 AM »
Hi Patrick,

Please post the model number of your sensors.
Some have pull up resistors that would raise the output signal voltage too high for a 5V input. Others have an open collector output that acts like a switch to ground and would work with Pokey directly.
Knowing which you have will make it possible to answer your question.

John

18
General Mach Discussion / Re: Rotator switch for Jog increments
« on: February 03, 2022, 05:51:34 PM »

Here is my crazy idea for the day, inspired by something Kfischer wrote.
Quote
Yep I will, I do some cutting manually with my mpgs.

It would be possible to use a 2 axis analog joystick and an Arduino to generate two quadrature signals with their speeds proportional to the joystick X and Y positions. If the MACH software can handle two encoder signals at the same time you could drive your spindle in any direction, at a controllable rate.

I played with an Arduino Nano this afternoon and generated a 4000 step per second quadrature signal.
Using Graig's suggested increment of 0.05mm, a 1 cm per second travel speed would only need 200 steps per second.

This looks like an affordable joystick. Better but more expensive ones are available.
https://www.digikey.com/en/products/detail/adafruit-industries-llc/3102/6152821.

Is this just a crazy idea or might someone actually find it useful?

John

19
Two 1N4148 diodes in series with the P12 power supply will drop the voltage at the BoB board to approximately 10 volts.

You could also use something from the 1N4001 series (1N4001 to 1N4007). The difference is the voltage rating which isn't not an issue in this use. They have a lower voltage drop so you would need to use three in series.

20
A0 is not a power supply, it outputs an analog voltage for metering that indicates a parameter like frequency or motor voltage. Have you actually measured 10 volts coming from that terminal? I checked the VFD manual and don't see how it could be forced to a constant 10V.

I can't find a manual for your rnrmotion mach3 bob. Its 10V terminal most likely does need to be connected to a power supply. The VFD P12 terminal is a 12V supply. Even though that's a bit it's probably OK to connect it to the BoB 10V terminal. A BoB manual should answer these questions.




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