Acorn Advanced Homing sequence to marker pulse

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martyscncgarage
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Re: Homing sequence

Post by martyscncgarage » Mon Dec 18, 2017 3:29 pm

diycncscott wrote:
Mon Dec 18, 2017 3:16 pm
No custom PLC needed, M105 and M106 look for the state of an input number, no PLC logic needed. You could set them to unused in the Wizard if you like.

M92 /Z L1 ;Move to Z+ home switch, back off until it clears.
M105 /Z P-4 F3 ;Move Z minus at 3ipm until input 4 closes
M26 /Z ;Set Z home here

M91 /X L1 ;Move to X- home switch, back off until it clears.
M106 /X P-3 F3 ;Move X plus at 3ipm until input 3 closes
M26 /X ;Set X home here

....lather, rinse, repeat

You may need to play around with the rates to get it to stop on the pulse. You can change the moves between looking for switch to open or close by changing the sign of the input # ie.. change -3 to 3
Thank you Scott! Besides addressing the challenge, there is good info in there as well!
I'll tinker around with it soon!
Marty
"Jack of all trades, master of none!"
Mesa, AZ

martyscncgarage
Posts: 946
Joined: Tue Mar 28, 2017 12:01 pm
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Location: Mesa, AZ

Re: Homing sequence

Post by martyscncgarage » Wed Dec 27, 2017 10:36 pm

diycncscott wrote:
Mon Dec 18, 2017 3:16 pm
No custom PLC needed, M105 and M106 look for the state of an input number, no PLC logic needed. You could set them to unused in the Wizard if you like.

M92 /Z L1 ;Move to Z+ home switch, back off until it clears.
M105 /Z P-4 F3 ;Move Z minus at 3ipm until input 4 closes
M26 /Z ;Set Z home here

M91 /X L1 ;Move to X- home switch, back off until it clears.
M106 /X P-3 F3 ;Move X minus at 3ipm until input 3 closes
M26 /X ;Set X home here

....lather, rinse, repeat

You may need to play around with the rates to get it to stop on the pulse. You can change the moves between looking for switch to open or close by changing the sign of the input # ie.. change -3 to 3
Scott, this worked great with a couple of tweaks,
Video here:


youtu.be/l1xUtRwN6T0

Here is the .HOM file code that worked for me (rear mounted tool post)
M92 /X L1 ;Move to X+ home switch, back off until it clears.
M105 /X P-4 F3 ;Move X plus at 3ipm until input 4 closes
M26 /X ;Set X home here

M92 /Z L1 ;Move to Z+ home switch, back off until it clears.
M105 /Z P-3 F3 ;Move Z minus at 3ipm until input 3 closes
M26 /Z ;Set Z home here
"Jack of all trades, master of none!"
Mesa, AZ

frijoli
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Re: Acorn Advanced Homing sequence to marker plulse

Post by frijoli » Wed Dec 27, 2017 10:58 pm

Outstanding! This is the right way to do this.

Clay
Clay
Outside Winston-Salem, NC

cncman172
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Re: Acorn Advanced Homing sequence to marker pulse

Post by cncman172 » Fri Dec 29, 2017 11:28 am

Marty, Scott

Nice video, good reference info. Lost of features are available from various drivers this is a good example of how to use some of them.

Russ

midy
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Re: Acorn Advanced Homing sequence to marker pulse

Post by midy » Fri Dec 29, 2017 12:22 pm

Good video again Marty. Would this also work with hybrid steppers as they have an encoder fitted?

martyscncgarage
Posts: 946
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Re: Acorn Advanced Homing sequence to marker pulse

Post by martyscncgarage » Fri Dec 29, 2017 12:23 pm

midy wrote:
Fri Dec 29, 2017 12:22 pm
Good video again Marty. Would this also work with hybrid steppers as they have an encoder fitted?
Must have a REFERENCE OUTPUT
I have not seen this on the hybrid stepper drivers.
"Jack of all trades, master of none!"
Mesa, AZ

martyscncgarage
Posts: 946
Joined: Tue Mar 28, 2017 12:01 pm
Acorn CNC Controller: Yes
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Re: Acorn Advanced Homing sequence to marker pulse

Post by martyscncgarage » Fri Jan 19, 2018 10:38 pm

UPDATED 1/25/18


DO NOT CONNECT THE DYN4 ENCODER OUTPUT TO ACORN INPUT PREVIOUSLY MENTIONED YOU WILL DAMAGE THE ENCODER .



Please NOTE: When you make up the custom .hom file, keep an updated copy in another directory. The Wizard WILL overwrite it with the default configuration .hom file.

Here is the .hom file used in this video:
M92 /Z L1 ;Move to Z+ limit switch, back off until it clears.
M105 /Z P-4 F1 ;Move Z minus at 1ipm until input 4 closes
M26 /Z ;Set Z home here

M91 /Y L1 ;Move to Y- limit switch, back off until it clears.
M106 /Y P-3 F1 ;Move Y plus at 1ipm until input 3 closes
M26 /Y ;Set Y home here

M91 /X L1 ;Move to X- limit switch, back off until it clears.
M106 /X P-2 F1 ;Move X plus at 1ipm until input 2 closes
M26 /X ;Set X home here

VIDEO TEMPORARILY REMOVED
Last edited by martyscncgarage on Thu Jan 25, 2018 10:52 pm, edited 1 time in total.
"Jack of all trades, master of none!"
Mesa, AZ

Reedfirst
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Re: Acorn Advanced Homing sequence to marker pulse

Post by Reedfirst » Tue Jan 23, 2018 11:50 pm

Hey Marty, any updates?

I've been following your threads about using the Marker Pulse for accurate homing and decided to give it a shot.

So I hooked up my oscilloscope to pin 4 on jp5 on one of my dyn4 drives and was able to verify the 5volt z+ pulse. It's just under 1ms long.

I believe you were suggesting to use a 2k 1/4 watt resistor to connected to the corresponding input that is connected to its respective drive and you seemed to have it working.

Brainstorming, I came up with the idea of using an N channel MOSFET. I just happened to have one in my junk drawer...

I connected the gate(Pin1) of the MOSFET to pin4 of the jp5 connector. The drain(pin2) of the MOSFET to Input 2 on the acorn, and the source(Pin3) of the MOSFET to ACORN Common.

I wrote a new home file, hit the "RESET HOME" button, and it worked! One thing I did notice is I'd like to clock my motors so that it is very close to the index pulse just after backing off the limit switches. (Especially on the Z axis as the travel is already limited on a bridgeport)

I'm still doing a few tests but I think this might be a viable approach. I'd like to find a popular MOSFET that will easily fit inside of a DB-9 backshell.

martyscncgarage
Posts: 946
Joined: Tue Mar 28, 2017 12:01 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
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MPU11 & GPIO4D -w/ 3rd Party Drives: No
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CNC11: Yes
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System Serial Number: none
Location: Mesa, AZ

Re: Acorn Advanced Homing sequence to marker pulse

Post by martyscncgarage » Wed Jan 24, 2018 5:46 am

Reedfirst wrote:
Tue Jan 23, 2018 11:50 pm
Hey Marty, any updates?

I've been following your threads about using the Marker Pulse for accurate homing and decided to give it a shot.

So I hooked up my oscilloscope to pin 4 on jp5 on one of my dyn4 drives and was able to verify the 5volt z+ pulse. It's just under 1ms long.

I believe you were suggesting to use a 2k 1/4 watt resistor to connected to the corresponding input that is connected to its respective drive and you seemed to have it working.

Brainstorming, I came up with the idea of using an N channel MOSFET. I just happened to have one in my junk drawer...

I connected the gate(Pin1) of the MOSFET to pin4 of the jp5 connector. The drain(pin2) of the MOSFET to Input 2 on the acorn, and the source(Pin3) of the MOSFET to ACORN Common.

I wrote a new home file, hit the "RESET HOME" button, and it worked! One thing I did notice is I'd like to clock my motors so that it is very close to the index pulse just after backing off the limit switches. (Especially on the Z axis as the travel is already limited on a bridgeport)

I'm still doing a few tests but I think this might be a viable approach. I'd like to find a popular MOSFET that will easily fit inside of a DB-9 backshell.


DMM is verifying that the 2k resistor will work long term.
Another issue is the Alarm signal, DMM pulses it and does not take it either low or high. Try it. Put everything on line and then just pull the motor encoder cable from the drive. That causes a fault. Look at input 5(assuming that's where you have the alarm connected). It pulses on and off. CNC12 does not see it as a fault. Also reported to DMM.

DMM also suggested not to power down DYN4 with a relay during Estop condition. You will loose your encoder position. Powering down just the motor power, using a relay(per The Dyn4 manual) tied to RL1(Estop relay on Acorn) and leaving the Logic power hot, seems to be the most intuitive. However, the very first time you power everything up and CNC12 closes the Estop relay, there is a motor lurch of about a quarter turn before homing. It only does this on power up.

I did update the video. I had said L1 in the .hom file referred to input 1, it does not. Cleaned up a couple other small things as well, which shortened it up a bit too.
"Jack of all trades, master of none!"
Mesa, AZ

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