Machsupport Forum

Mach Discussion => FAQs => Topic started by: $cott on June 26, 2015, 10:48:06 AM

Title: Whats is most actuate set up for limit switches
Post by: $cott on June 26, 2015, 10:48:06 AM

I am using MACH4 with a ESS controller I would like to very accurately home each time my machine starts up.  I need to be able duplicate my home position every time so i can place parts in a automation project i am building.  Is there any one on the form with some experience how to best approach this type of thing.

I am guessing an optical limit would be best ... any feedback would be appreciated.

Scott

Title: Re: Whats is most actuate set up for limit switches
Post by: BR549 on June 26, 2015, 11:12:23 PM

The most accurate way is to use a switch(your choice) to do a rough home to then use an encoder index mark to set the Actual HOME position. it is VERY accurate when used properly.

(;-) TP

Title: Re: Whats is most actuate set up for limit switches
Post by: $cott on June 29, 2015, 11:49:45 AM

thank you for you feedback ... I have not used an encoder before.  Are they attached to back side of the steeper or to the shaft in some type of manner.  Are there any preferred suppliers or websites I can educate my self on there use.

Scott

Title: Re: Whats is most actuate set up for limit switches
Post by: BR549 on June 29, 2015, 03:26:38 PM

One way would be to mount an optical switch on the table itself. This eliminates any backlash of the drives/screw .   Set it up as a HOME/limit if you want
Then HOME to the switch as a rough set THEN drive back into the switch until it sees the retrip of the optical switch using a macro and G31. That will get you a homing solution theoretical accuracy of 1 step value

OR you could use a rotary encoder with INDEX and mount it on the screw or on the motor iteself. YOUR choice.

You can wrap all the needed code into a button for each or ALL axis.