[FelixPQ]

When using the parallel port, and homing a slaved axis, each side homes to the switch. To square the gantry, the switches must be moved to the correct location for this to occur. Mach3 has no ability to change the amount that it backs off the switch.

If you use a motion controller, things may be a little different. This is because the motion controllers handle the homing, not Mach3. I believe that some motion controllers allow you to independently set the amount that the master and slave back off the switch, to square the machine.

I don't think any motion controller uses a formula or calculation to square a gantry. It just moves the gantry sides to the positions that you tell it.


As for Formulas. Yes, a formula can be used to compensate for an out of square gantry. But there's a good chance that you'll run into a situation where the machine is moving without using the formula. This is due to bugs in Mach3. I've posted the exact situation somewhere a few years ago I think, but don't recall the exact circumstances. What happens is that the formula is ignored in some situations. When the formula starts working again, Mach3 enables the formula, and the axis tries to "jump" into the correct position required by the formula, and you'll lose steps.

I understand exactly what Mach3 does and it implies the switch/sensor are installed square to begin and if for any reason the gantry gets "unsquare" the homing routine can, if you have set things up correctly with Mach3, bring the gantry back square relative to the switch and or sensor.

I'm sure you understand clearly the difference in what I'm saying, essentially, Mach3 does a simple physical squaring base on the switch/sensor position and I would like Mach3 to do both a physical and a logical squaring base yes, on a physical position and also on a specific offset and this implies the switch/sensor don't need to be installed as perfectly square as in the current case with Mach3. IMHO this would bring the achievable accuracy a bit closer to perfection but the real question is probably, is this really necessary?

Though I haven't done it yet, I'm quite sure I will install my sensors to make the gantry plenty enough square even if take a lot of time and I'll be satisfied with the result no matter what.

While I'm at it, I just love your 2010 screen set and thank you for your input.

Thanks,
Yves

[SScnc]

I need some advice please....

I've been using these sensors for homing on my CNC router for a few years and they've been working great. I have also been using one Dell PC to switch between my mill and the router via an A/B switch and separate Mach3 profiles for each machine.

I just setup a dedicated Dell PC for my router and copied the router XML over to it. All settings and functions are exactly the same as they are on the older PC and everything works perfect except the sensors always show active in the diagnostics screen in Mach3, i.e., red led's.

My hall sensors have actual red led's and they light up as they should when the gantry approaches them and go dark as they should too.

I've triple checked all the settings in ports and pins and they are set the same as on the old PC. I even hooked the old mill PC back up to the router just to check and the sensors work fine. I can't figure out why !

BTW: I'm running a G540 on the router. And both PC's are running XP pro.

Any suggestions ?

[SScnc]

OK, after a LOT of searching and reading, and not finding anything even close to my problem I finally found a solution.

I found that I had to place a 3.3K resistor inline with the negative switched leg from the hall sensor module from each axis. Even though I had used a sensitive analog meter to see if there was any "bleed through" and the needle didn't show anything. But there must have been some getting through. I had also temporarily added another pull up resistor but surprisingly that didn't help either, the home LED remained lit on Mach's Diagnostics screen.

I was about ready to get a different PC as I thought there must be something wrong with my motherboard's parallel port, glad I kept trying ! Strange how the additional 3.3K's aren't needed when using the other PC with Mach.

Wanted to follow up with my solution in case anyone else ever has this irritating problem.

[naspc]

Hi, has anyone tried wiring hall sensors to a leadshine MX3660 controller?

http://www.leadshine.com/productdetail.aspx?type=products&category=accessories&producttype=multiple-axis-stepper-drives&series=MX&model=MX3660

[dsnellen]

Hi, has anyone tried wiring hall sensors to a leadshine MX3660 controller?

Leadshine Technology Co., Ltd.

Yes. Look at Figure 15. The MX4660 allows you to use a different pull-up voltage for the inputs if you like -- this can be handy if you want to run 24V powered IO, etc. If you are using just mechanical switches or IO that works off of 12V, it is simplest to just connect 12V to OPTO1 and OPTO2.

[naspc]

Thanks for the reply but I have the MX3660 version. I drew up a diagram on how i think it should be wired up.

[pinchio]

What is required to add another LED to indicate normal state (green led). The LED would switch off and the red led would come in when the switch is triggered by the field.

Any assistance with actual part number from digikey and wire up schematic would be appreciated for this electronic newbie.

Thank You

[x2df]

What is required to add another LED to indicate normal state (green led). The LED would switch off and the red led would come in when the switch is triggered by the field.

Any assistance with actual part number from digikey and wire up schematic would be appreciated for this electronic newbie.

Thank You

If you are using an LED with less than 20mA supply current, you can use any (preferable a XOR GATE in this situation) Logic Gate. Simply wire the cathode to the output of the LED and wire the Anode of the green LED to the Output of the same logic gate. When the switch is on, it will show as green, supplying the Green LED with current, when the Switch is tripped, it would allow the Logic gate to 'sink' the current of the Red LED.

The input to the Red LED would be just powered from 5 volts or whatever voltage you have, with respect to the proper resistor in line to supply the proper forward voltage of the LED.

The Hall Effect Sensor output would got to one of the A or B inputs of the Logic Gate, (instead of the Anode of the LED as before), and the other input of the logic gate would be connected to ground. Most CMOS Logic Gates will Sink or Source up to 25mA, any more than that, you'll destroy the logic gate. But Your LED's will most Likely reach enough (if not full) brightness at around 10mA anyway.

[jlandry]

Thanks for the reply but I have the MX3660 version. I drew up a diagram on how i think it should be wired up.

Naspc, have you tried wiring this up yet? I also have the MX3660 and am looking to connect hall effect sensors.

[nlancaster]

Just buy x2df's kit. Works awesome and looks great!

[blitz355]

Is there a way to keep a controller from moving back outside of the hystersis? When homing my y& slaved a axis, one axis moves for a moment longer than the other (moving away after contact). It's very difficult to get the slaved axis to actuate at the exact same spot as the other.

[RonaldoNZ]

That's by design in order to square the axis.

Sent from my SM-N9005 using Tapatalk

[blitz355]

That's by design in order to square the axis.

Sent from my SM-N9005 using Tapatalk

What? Making it difficult to actuate at the same time? Lol

[RonaldoNZ]

What? Making it difficult to actuate at the same time? Lol

Treat one sensor as fixed and the other you need to tune/position. I wouldn't call it difficult

Sent from my SM-N9005 using Tapatalk

[justCNCit]

Hello, I've been trying to hook up this circuit with the hall effect sensors directly to the parallel port without success.

I have an external 5v power supply. Is the key to use a common ground? Mach 3 registers logic change when parallel port input is closed to parallel ground. The Hall effect puts out 5v relative to its own ground using multimeter, when a magnet is next to the switch. Is a transistor required in order to connect these two circuits?

Thanks
Shawn

[x2df]

Hello Shawn,

I know that some breakout boards, like the G540 if I remember correctly, is kinda touchy and doesn't operate correctly unless the ground pins of separate supplies are tied together creating a common ground point.

Also, you may need to have a diode inline with the circuit to the parallel input. try that.

If you are on a laptop using a parallel port ONLY with mach 3 you may experience other problems than just this as well. If I remember correctly, Laptops using parallel port work okay with Windows 95/98 (or XP too?), but any newer version of windows on a laptop with a parallel port and Mach 3 has problems. In those cases, you would need to get a smoothstepper and use the ethernet or USB ports. Or use a Desktop machine all together. In either case, a Smoothstepper will improve overall performance for you machine no matter what operating system you have on your PC.

[x2df]

depending on your switch configurations as well, you need to program Mach 3 for normally Open (NO) or Normally Closed (NC) limit switch operation. These hall switches are designed to work as Normally closed, sinking the ground from the parallel port. Once that ground point is severed (switch unplugged or wire cut), it becomes an open circuit.

For example, the G540 has an internal optical transistor (Optocoupler which has an LED that operates a transistor). The ground point, or the cathode side of the LED, is connected to ground, the LED turns on which turns on the Transistor which activates the software to say the limit switch is on. In this case, this would be a normally closed switch. The Limit switch would go between the LED's cathode and the ground point, almost as if you placed a mechanical switch there to complete the closed circuit. This is idea for a perfect SAFELY operated machine. Because if the wiring for the limit switch is accidentally cut or has become unplugged, it would stop the LED from emitting light, thus turning off the transistor, notifying the software program that the circuit is open. So in this case, Mach 3 would have to be configured as a Normally Closed (NC) switch operation.

The switches I have designed, can be configured for both NO or NC operation with the help of a combination of logic gates and optoMOS (same as Optocoupler but uses a mosFET instead of Transistor).

Hope that helps.

[justCNCit]

Hello, after struggling for a couple days on this I followed this article to success today:

https://electronics.stackexchange.co...el-port-inputs

Requirement was a common ground for both circuits. Signals register fine in Mach 3. I am using the G540 but to my knowledge it should ignore unused pins. I have a 4 axis machine and have had problems with maintaining maching position in between tool changes. I make wood signs and based on dial indicators, the motors wander on startup (10+ hour tool paths sometimes) and even a 0.002" change seems to muck up the work.

Wanted to get a proper breakout board as well but have to generate work before making any purchases and shipping to Canada is very expensive even though CNC4PC has some nice stuff. Using a PC for control so a solid +5v from the parallel port isn't an issue. But beginning to see the merits of using USB although I have a second parallel port card.

[x2df]

There's really no need to get a 'proper breakout board'. That G540 is an excellent breakout board. Only reason to upgrade or get better is if you upgrade your machine and start running bigger motors.

[justCNCit]

you have to be kidding me. Thanks for the info, that saves me some money today.

Another question on the Hall Effect switches, is that Mach only seems to pickup once the switch has turned on and then off. Is the hall effect still repeatable and accurate being used like that? I think Romano called this hysteresis, or is this some random value of field distance. Thank you