I have been working on creating a new hex file for the E-Stop problem.
I have not gotten my setup right as I am getting an error with the source.
Once I get past the error then I will compile a new version of the source code that will stop the steppers.
Yes the back emf from the motors will discharge through the board as suggested prior. I was not aware before people wiring up the switch to the power supply. I would have warned against it before.
May take me a couple of days to get things going.
The source uses old files that are now depreciated and the changes were not updated in the source. I have not been doing a lot of coding so I am working out the issue.
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What I am trying to do is create a new update to allow an E-Stop connection for stopping the motors using a interrupt and not hooking it up to any power pins. I just relized I was using the wrong source. I should be able to get a new file and all you will need to do is hook up the switch to a pin on the shield and it will stop the motors. This is the proper way and the larger controllers have this built in. Why it was over looked I do not know. I will document this and submit it to the creators to hopefully make the changes and I will include a wiring diagram.
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I think you miss the point of an E-stop. You are trying to minimize damage to a system that has gone berserk. You cannot rely on code running on a microprocessor.
If grbl is still functioning you can use feed hold to stop the machine immediately.
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I have researched the controller and its signals. There is a stop for them to disable the motors that can be achieved using the MCU. If the MCU is not sending any commands then the motors will not be moving. Using the PSU and breaking the power to the motors does not stop them when you turn it back on. This is a destructive path as it can lead to failures to the electronics later if not immediate.
I can set up a Hardware stop but it does not stop the codes streaming into the controller. Need a solution that stops the stream and signals the H-Bridges to stop the motors.
The motors cannot move without a pulse signals from the MCU. So in this case a sw hooked up and set up to activate the disable motors pin that is on the controller is a good idea and will work. If I am successful I may be able to have a E-Stop that not only works but will allow you to continue if you want. Meaning it will allow you to zero out then restart where you left off assuming that not too much damage was done.
Search for Feed Hold and Cycle start.
I use E-Stop to cut AC power and trigger limit Z axis as well.
The machine will stop immediately .
I have done some testing and found a way to stop the machine dead cold without removing the power by disrupting it at the power supply. I will be creating a schematic and instructions soon.
This will be a handy thing to prevent damage to the circuits.
This will stop the machine cold. Even the spindle/router.
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This is awesome! Looking forward to it!
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the chips dump (regenerated power) the feedback from the steppers back on the power supply.
The data sheet shows a capacitor to absorb this power.
On my robot I use a diode on the switch so the power makes it back to the battery no matter the switch is on or off.
If the e-stop was a double pole we could shunt the power through a resistor.
2 hours from Inventables, and near a place called speedy metals???
Damn man, I need to move to your neck of the woods!
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You lucky “Summa-ma-Bi*%!” LOL
Where could a fella click, to find info on some shiny, sexy hardware like that?
Here is a 4.75" unit.
http://www.ebay.com/itm/Z-Axis-CNC-4-75-Fast-Travel-ANTI-BACKLASH-Linear-Slide-Router-Actuator-/162201386642?hash=item25c3f4be92:g:tt8AAOSwYudXG654
and the one I picked up and am running.
http://www.ebay.com/itm/Z-Axis-5-75-Fast-Travel-ANTI-BACKLASH-Linear-Slide-CNC-Router-Actuator-/162196901958?hash=item25c3b05046:g:tt8AAOSwYudXG654
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In your opinion what is the main advantage of the larger unit?
In all honesty, I could have gone with the 4.75" unit but wasnt paying close enough attention since I was having a few unrelated distractions when I was placing the order.
But I have no complaints with what I did get since if I decide to make an upgrade similar to what Phil is doing or add a fourth axis or ??? I have the capacity to do so.
One thing is for certain, if something goes awry, and the z starts heading for the ceiling, I have time to address it before it tops out at the top of the axis.
Today i rewired my x-controller to cut dc power in stead of ac. Then bypassed the ac estop as a must. (found out the hard way it wont turn on unless u short the 2 wires). i found that it stops everything almost immediately. Anybody see a flaw?
They are a lot cheaper than I expected and shipping to Australia is reasonable as well (<$US40).
One day …
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This is what you started the thread with “no play”. Have you already tried to measure the flex in your Z axis with this new setup?
For reference: Stepcraft publishes 0.07 to 0.12mm at 2kg on their machines
My unmodified 500mm ShapeOko2 had 0.55mm at 10kg and 0.17mm at 10kg after reinforcing the X beam and Z axis wheel tensioners/spacers (measured at the bottom of the Z axis carriage plate.
I will second the “see the difference” statement. I have the same linear z unit and the improvement has been remarkable. What little chatter i had with the original unit is gone and the whole machine runs much quieter with the upgrade.
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Good to hear that it works, especially when you plan to raise the Z height.