External variables

Read/write accesses to channel-specific and global external variables V.E.* can be made from the realtime cycle.. The variable must be defined as synchronous for a write access.

Programing Example

Definition of a synchronised V.E. variable

...

var[0].name                      VALUE1

var[0].type                      REAL64

var[0].scope                     GLOBAL

var[0].synchronisation           TRUE

var[0].access_rights             READ_WRITE

...

Only synchronised variables may be written in realtime cycles.

With a read access to a V.E. variable, its value is dependent on its synchronisation.

• A synchronised variable is evaluated in the realtime context of the CNC.
• An asynchronised variable is evaluated at the time of decoding and is used as a constant.

Programing Example

Accesses to V.E. variables

; Pre-assign variables

V.E.SYNC = 47 ; synchronous variable

V.E.SYNC = 11 ; asynchronous variable

; Define realtime cycle

#RT CYCLE [SCOPE = PROG]

  ; Run through instructions only once

  $IF ONCE 1 < 2

    ; Assign new value

    V.E.SYNC = 99

    ; has the value 198

    V.E.VALUE1 = 2 * V.E.SYNC

    ; V.E.ASYNC always has the value 11 in this realtime cycle

    ; right side has the value 22

    V.E.VALUE2 = 2 * V.E.ASYNC

  $ENDIF

#RT CYCLE END

; End main program

M30