FANUC Karel vs TP: When to Use Each

A practical guide to when FANUC Karel outperforms TP and vice versa. Covers file I/O, string handling, math operations, and real-world examples of hybrid Karel+TP programs.

FANUC robots have two native programming environments: TP (Teach Pendant) and Karel. Most integrators use TP exclusively — but Karel unlocks capabilities that TP simply cannot match. Knowing when to reach for each tool is what separates an intermediate programmer from an expert.

What Karel Can Do That TP Cannot

When TP Wins

For motion, I/O, and anything an operator needs to read or modify on the teach pendant, TP is always the right choice. TP programs are visible in the pendant editor, have built-in position teaching, and are understood by every FANUC-trained technician. Karel programs are compiled binaries — operators cannot view or edit them without a PC and the Karel compiler.

A Real Example: CSV Recipe Loading

A palletizing cell uses 50 different product recipes. Each recipe defines layer patterns, product dimensions, and approach offsets. Storing this in TP registers is impractical — 50 × 10 values = 500 register writes every changeover. The solution: one Karel program reads the recipe CSV on startup and writes values to Numeric Registers, which the TP motion program then reads.

PROGRAM recipe_load
%NOLOCKGROUP
%NOPAUSE = COMMAND + TPENBL
VAR
  f_id   : FILE
  fname  : STRING[32]
  val    : REAL
  i      : INTEGER
  status : INTEGER

BEGIN
  fname = 'FR:RECIPE01.CSV'
  OPEN FILE f_id ('RO', fname)
  FOR i = 1 TO 10 DO
    READ f_id (val)
    SET_REG(i, val, status)
  ENDFOR
  CLOSE FILE f_id
END recipe_load

Calling Karel from TP

  1: CALL RECIPE_LOAD    ;  ! Run Karel program
  2: WAIT R[1]>0          ;  ! Wait until R[1] populated
  3: J P[1:HOME] 100% FINE ;