A practical introduction to ABB RAPID — MODULE structure, PROC and FUNC, MoveJ/MoveL/MoveC, data types, and a complete pick-and-place routine.
RAPID is ABB's robot programming language, and it is more expressive than FANUC TP. Where TP is a line-numbered instruction list, RAPID is a structured language with modules, procedures, functions, typed variables, and control flow. If you have programmed in Pascal or C, RAPID will feel immediately familiar.
RAPID Program Structure
A RAPID program consists of MODULEs. Each module contains data declarations (VAR, CONST, PERS) and routines (PROC, FUNC, TRAP). The entry point is always a PROC named main.
MODULE MainModule
! Persistent variable — survives power cycle
PERS num partCount := 0;
PROC main()
! Main entry point
MoveAbsJ homePos, v100, fine, tool0;
WHILE TRUE DO
PickPart;
PlacePart;
partCount := partCount + 1;
ENDWHILE
ENDPROC
PROC PickPart()
MoveJ approachPick, v500, z50, gripper;
MoveL pickPos, v100, fine, gripper;
SetDO DO_GripperClose, 1;
WaitTime 0.5;
MoveL approachPick, v200, z50, gripper;
ENDPROC
PROC PlacePart()
MoveJ approachPlace, v500, z50, gripper;
MoveL placePos, v100, fine, gripper;
SetDO DO_GripperClose, 0;
WaitTime 0.3;
MoveL approachPlace, v200, z50, gripper;
ENDPROC
ENDMODULEMotion Instructions
The three core motion types:
- MoveJ — joint motion, fastest, non-linear path. Use for repositioning between operations
- MoveL — linear TCP motion. Use for approach and departure moves near fixtures
- MoveC — circular arc through a midpoint. Use for arc welding, dispensing, sealing
Zone Data: z0, z5, z50, fine
Zone data controls path blending — how closely the TCP passes through a point before moving toward the next. fine means the robot stops exactly at the point. z50 means the robot starts moving toward the next point when the TCP is within 50mm of this point. Use fine for picks, places, and contact. Use z50 or larger for intermediate waypoints.
RAPID is compiled and checked by RobotStudio or the FlexPendant editor. Syntax errors are caught before execution. Always compile and simulate in RobotStudio before uploading to a real robot.
