Re: STG2

["Jan" <jan-at-chocolateworld.be>]

John wrote,
>
>I wiped the HD yesterday, reinstalled RH6.0, installed RTL2.0 then
installed
>the May release of EMC - still using the stg2mod.o motion controller.
There
>was no difference.  It's actually kind of weird, when I measure DAC0 it
will
>creep up slowly (ramping up), but DAC1 and DAC2 will both spike.  In fact,
no
>matter which direction button I press, DAC1 would still go positive!?

It seems to me that your encoders are give the wrong signals, start-up the
stg-soft for encoder input, if you turn now manually in two directions you
have to see the counts go up and down if this is not the fact , say your
counts are only get up or down it is normal that the DAC will sent output in
one direction.

The spikes could come from the fact that no encoder signals are received by
EMC.
This was a problem I had myself. It made my old milling machine act like a
spitfire... . So if you ask me both problems can be seen as encoder
problems. EMC is a closed loop system with the STG-Board.

There is also a utility in the plat/linux/bin directory called stg2diag that
captures the
encoder data and shows it, when encoder impulses are received to fast it
will generate a CR so you can closely examine.
With this utility I saw that my encodersignal was flipping between 1 and
env. 65000 and belief me or not tweaking the bios solved the problem.

>(Another weird thing is that if you change the settings on one axis, it
seems
>to change it for all axes.)  I would suspect the board, but there are
>separate opamps for 0&1, 2&3, etc.  If 0 works, why not 1?  Plus I've been
>able to manually set voltages on it.  I think something may be getting put
>together (the way the base address is appended to the DAC and the counts)
>wrong when it writes to the DAC.

Try to run the board on a different base-address?

>-John
>
Jan.