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Author Topic: Homing Slave Estops system  (Read 3711 times)

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Homing Slave Estops system
« on: April 13, 2009, 08:11:47 PM »
I have searched the forum I have not really found the problem that I am currently having.
I have the system set up to home the slave (A) with them master (Y).  Two motors to move a carriage.  I have a switch on either end of the Y side of the carriage in serial to one input. Y++,Y-- and Y Home.  I also have the same setup on the A side of the carriage.  All of these switches are in series to a different input. A++, A-- and A Home.

When I "ref all" the carriage moves towards home, hits the home switches for both Y and A.  It then moves off of the switches but when it comes off of the Y home switch first, it estops with the A home switch still active.  I assume that it is estopping because it comes off of the Y home and thinks its done but then it see that a switch is made and estops.

When it homes it doesn't appear to straighten the carriage by also homing off of the A side of the carriage.  Am I missing a setting or pinout somewhere?

Thanks
Todd
Re: Homing Slave Estops system
« Reply #1 on: April 14, 2009, 08:56:19 PM »
Update--
After some testing I still can not get the slaved A axis to home after the master Y axis.  The A axis does move to home with the Y axis, but while homing the system does not even look at the inputs for the A axis even though when tripped all of the inputs show up in the diag screen as M4++ limit, M4-- limit and M4 Home.  It appears that it is only looking at the home switches for the Y axis???

Any ideas?

Thanks
Todd

Offline jimpinder

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Re: Homing Slave Estops system
« Reply #2 on: April 15, 2009, 07:19:07 AM »
We had a few months ago, exactly this query. The way the "homes" work is each axis moves singly, and, yes, Mach is only looking for a signal from that axis, It then does the other axis. The problems then start, becasue if one of the switches is tripped out of sequence, the switches act like limits and stop all movement.

I did not follow the post to it's conclusion, but seem to think that there is a way to "slave" both axis together and have the "home" acting together. Another search is called for, unless the "poster" points the way to it.
Not me driving the engine - I'm better looking.

Offline Hood

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Re: Homing Slave Estops system
« Reply #3 on: April 15, 2009, 07:24:33 AM »
Never had a slaved axis but thinking you may need the Home Slave with Master option checked, its in the General Config, do you have that?
Hood

Offline Greolt

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Re: Homing Slave Estops system
« Reply #4 on: April 15, 2009, 07:55:33 AM »
If you have a Y home switch and a A home switch then I presume you want to "square the axis" when homing.

If you "home slave with master" then you might as well ditch the A home switch. It will be ignored.

If it were me I would disable the limit switches until you get the homing happening as expected.  Deal with one thing at a time.

Y needs to home first then A, so in your Ref ALL button make sure "DoButton(23)" is happening before "DoButton (25)"

Sequence is, Y homes and A travels along with it,  then A homes all on its own as Y stays still.

Greg
Re: Homing Slave Estops system
« Reply #5 on: April 15, 2009, 09:35:05 PM »
Thanks to all who replied.  It helped.

Well I got it working but I still don't understand why it is working.  I had the "Home Slave with Master" checked so that both Y and A axis would home together and not rack my carriage during a Ref All.  I though thats what "Home with Master" did.  If I UN-CHECK "Home with Master" the slave homes with the master and then homes itself.  Just like it should.  With "Home with Master" unchecked why is A homing with Y?  Is it just because I have them slaved?

Thanks
Todd

Offline Greolt

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Re: Homing Slave Estops system
« Reply #6 on: April 15, 2009, 10:34:07 PM »
Yes because they are slaved.

Can you imagine Y trying to travel on its own without A following along?

Greg