controlling direction of rotary index motion

[rcs60]

i am working on an okuma 4020 vmc with an osp200m control with a tsukadoma rotary table
the problem i am having is to keep the rotary from indexing the part under the rotary (more than 180. degrees) on start up
I am looking for the shortest path back to 0.degrees if an operator jogs the rotary off of the a0. or a way to determine the actual position and use the m15/m16 codes to get the direction correct

Similar Threads:

• Need Help!- Jerky motion in one direction - x axis
• Rotary Table Index Motion Controller?
• controlling rotary axes

[deadlykitten]

hy rcs

i am using a small code to get the shortest path for the C axis on lathes; i use this inside the program :

    // some linear movement
    CALL OCAXS LV01 = desired_C_value
    // C axis movement

and i keep this soubroutine inside a *.ssb file :

OCAXS ( C_target )


  IF [ ABS [  LV01 ] LT 360 ] NJUMP1
       NLOOOP M0 ( cool man )
       GOTO NLOOOP
  NJUMP1 NOEX


  IF [        LV01   GE   0 ] NJUMP2
         NOEX LV01 =  360 +  LV01
  NJUMP2 NOEX LV01 = LV01 - VSIOC


  IF [ [ [ [ [ LV01 GE 0 ] AND [ LV01 LE +180 ] ] EQ 1 ] OR  [ LV01 LT -180 ] ] EQ 1 ] NTRUE
    ( NFALSE ) M16
               GOTO NDONE
      NTRUE    M15
      NDONE    NOEX


RTS ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . )

 (      dif >  +180 : M16 )
 ( 0 <= dif <= +180 : M15 )
 ( 0 >  dif >= -180 : M16 )
 (      dif <  -180 : M15 )

... it checks that -360 < target_value < +360
... converts negative value to positive ( eq -30 to +330 )
... it chooses a sense

to make it work on your cnc, you need the "equivalent system variable" for "VSIOC"
... i don't know, try VWKA* , VWKB*, * = A or B or C ?

kindly

[rcs60]

I found a solution to making sure the rotary does not swing the part under the rotary if an operator manually jogs it off 0 degrees
m403 will make the rotary take the shortest path