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servo won't engage
« on: December 23, 2008, 09:09:32 AM »
hi
i have had my plasma table running for 6 months on belts
and decided to go for rack & pinion drive. all worked fine until my
servos do not engage anymore .
I have a button on my controller (logitroll 20 amp ametek servos )that
if i push up for 3 sec it engages (activates ) the servos or from
active mode if pushed down deactivates the servos.
when my computer is of or if i unplug the parallel cable from computer
,i can activate the servos everything is OK
but when the computer is on (does not mater if mach is running or
not)the servo do not engage.
when i push the button to activate the servos they try to move and
deactivates
or if i keep the button pressed the 3 axis move rapidly and get
deactivated and move again (hi speed very short moves ) and so on
until i release the button.
there is another situation when i unplug the parallel cable, activate
the servos then plug back the cable and play whit it like everything is OK
please help

Offline Hood

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Re: servo won't engage
« Reply #1 on: December 23, 2008, 11:40:13 AM »
You will have to provide more info, especially the type of drives and where that switch comes into the equation. Did you build the machine yourself or is it a bought machine? Do you have a wiring diagram?
Hood
Re: servo won't engage
« Reply #2 on: December 23, 2008, 12:06:01 PM »
hi hood

it is a 20 amp servo pak ametek servos/us didital encoders from "lowcostcncretrofits"
the machine it is build by my
inside the controller box are 3 gecko320 drivers
the machine did run well before the modification
it runs well at this moment if i unplug the parallel cable from the comp /engage the servos/plug back the parallel cable and then jog around
or if i go in device manager /disable the parallel port/engage the servos/enable the parallel port and then jog around
i have fitted a second parallel port on the comp /set it as port 1 in mach but the problem is still there
i measured the voltage across the parallel cable (unplug-ed from the controller box ) and found 5 v on pins :3,7,8,10,11,12,13,15.
from those pins3 and 7 that have 5v on them corespond to x dir and z dir
my setup for the 3 axis is as follows:
     step     dir
x     2        3

y     4        5

z     6        7
Re: servo won't engage
« Reply #3 on: December 23, 2008, 12:23:32 PM »
if i disable  port1  in mach or if mach is not running the problem is still there

Offline Hood

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Re: servo won't engage
« Reply #4 on: December 23, 2008, 02:38:15 PM »
Where/how is the switch wired? Is it to the Geckos?
Hood
Re: servo won't engage
« Reply #5 on: December 23, 2008, 02:42:45 PM »
yes
is bewin pin 5 and pin 12 on geckos and - one side of swich goes to grouund  (0 v )

Offline Hood

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Re: servo won't engage
« Reply #6 on: December 23, 2008, 02:54:06 PM »
I am not familiar with Geckos servo drives but will look and see what these pins correspond to.
Hood
Re: servo won't engage
« Reply #7 on: December 23, 2008, 02:55:36 PM »

Offline Hood

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Re: servo won't engage
« Reply #8 on: December 23, 2008, 03:14:57 PM »
OK so do you have a wire going back to the computer to signify the fault? If so then do you have that wired properly and set up properly? I would presume you have that to Input  1 in mach?
Hood
Re: servo won't engage
« Reply #9 on: December 23, 2008, 03:19:59 PM »
the only wire going to comp is parallel cable
yes is set to port 1 in mach
and i veryfied the wiring to encoders and motors and is ok