&ACCESS RVP
&REL 1
&PARAM TEMPLATE = C:\KRC\Roboter\Template\vorgabe
&PARAM EDITMASK = *
DEF basic_handshake()
; ================================================================
; Basic I/O Handshake Pattern
; ================================================================
; Demonstrates simple bidirectional signaling between KRL and Python
; via digital I/O channels.
;
; Python-KRL Coordination Flow:
; 1. KRL signals "ready" to Python (output 1)
; 2. Python waits for signal, then processes
; 3. Python signals "complete" to KRL (input 1)
; 4. KRL waits for completion signal, then continues
;
; Python Code Example:
;   api = RSIAPI('RSI_EthernetConfig.xml')
;   api.start()
;
;   # Wait for KRL to signal ready
;   if api.krl.wait_for_signal(1, timeout=10.0):
;       print("KRL is ready!")
;
;       # Do Python processing here
;       time.sleep(1.0)
;
;       # Signal completion back to KRL
;       api.krl.signal_complete(1)
;
;   api.stop()
; ================================================================

  ; Variable declarations
  INT i
  BOOL python_ready

  BAS(#INITMOV, 0)  ; Initialize motion

  ; ============================================================
  ; STEP 1: KRL signals ready to Python
  ; ============================================================
  $OUT[1] = TRUE   ; Signal ready on digital output 1
  WAIT SEC 0.1     ; Brief delay for signal propagation

  ; ============================================================
  ; STEP 2: Wait for Python to acknowledge completion
  ; ============================================================
  python_ready = FALSE
  i = 0

  ; Poll input 1 until Python signals completion (max 10 seconds)
  WHILE (python_ready == FALSE) AND (i < 100)
    IF $IN[1] == TRUE THEN
      python_ready = TRUE
    ELSE
      WAIT SEC 0.1
      i = i + 1
    ENDIF
  ENDWHILE

  IF python_ready == TRUE THEN
    ; Python signaled completion successfully
    ; Safe to proceed with robot motion

    ; Reset handshake signals
    $OUT[1] = FALSE

    ; Example motion with Python coordination
    PTP HOME Vel=100 % DEFAULT
    ; Python can send corrections during motion via RSI

  ELSE
    ; Timeout - Python did not respond
    ; Halt program for safety
    HALT
  ENDIF

END