Heidenhain TNC controls run Europe’s mold, die, and five-axis rooms, and they speak their own language: Klartext, literally plain text. Machinists meeting it from the Fanuc world, or leaving it for one, often expect a menu system. It is not. Klartext is real, typed, line-by-line programming, which makes the comparison with Fanuc-style G-code a translation table rather than a philosophy debate.
What does Klartext actually look like?
Readable motion, one dialogue line per move:
TOOL CALL 5 Z S2500
L X+50 Y+20 R0 FMAX
L Z-5 F200
CC X+50 Y+30
C X+60 Y+30 DR+L is a straight line (FMAX makes it a rapid), TOOL CALL loads tool 5 with its length axis and speed, CC sets a circle center, and C cuts the arc around it. The control prompts for each element as you type, which is the conversational part, but the finished program reads top to bottom exactly the way you read any code.
How do the two languages map?
Almost one to one, which is the good news for anyone crossing over:
| Concept | Klartext | Fanuc G-code |
|---|---|---|
| Rapid move | L X+50 R0 FMAX | G00 X50. |
| Feed move | L X+50 F200 | G01 X50. F200 |
| Arc with center | CC X+50 Y+30 then C ... DR+ | G02/G03 with I, J |
| Tool change + length | TOOL CALL 5 Z S2500 | T5 M06, S2500 M03, G43 H05 |
| Drilling cycles | CYCL DEF cycles | G81, G83 canned cycles |
| Variables | Q parameters | Macro variables |
Two rows reward attention. The arc row shows Klartext separating the center (CC) onto its own line with DR+ or DR- giving direction, where Fanuc packs center and direction into one block, the same geometry as the I and J calculation. The tool row shows one Klartext line doing what Fanuc spreads across three, which is why Fanuc feels verbose to TNC hands and Klartext feels magical to Fanuc hands.
Which one should you learn, or learn first?
The machine in front of you decides the first language; the market decides the second. Klartext mastery is deep but stays within Heidenhain’s world, while word-address G-code runs on nearly everything, the universal core included on TNCs themselves through their DIN/ISO mode. The career-shaped version of this question, with the cases where conversational-first genuinely wins, is treated in is it better to learn conversational or G-code first, and the same portability logic plays out on the Siemens side in ShopMill vs ISO G-code.
A concrete crossover pattern: a German mold maker with a decade of Klartext joined a job shop running Fanuc verticals. He printed the mapping table above, drilled the word-address vocabulary for three weeks, and reported the strangest part was not the codes but the absence of dialogue prompts: Fanuc waits silently while you type the whole block yourself.
What stays the same underneath?
Everything that matters most. Offsets locate parts and tools on both, prove-out discipline is identical, modal state must be tracked on both, and a wrong number crashes either machine with perfect impartiality. Reading skill transfers too: the block-by-block narration habit from how to read a CNC program works on a Klartext listing unchanged. The languages differ; the machining does not.
Bottom line
Klartext is Heidenhain’s readable dialogue code, closer to G-code than to menu programming, and the two map nearly line for line: L to G00/G01, CC plus C to the arc family, TOOL CALL to the tool-change trio. Learn the language your machine speaks, keep the mapping table close when crossing, and drill the word-address core on the G-code practice hub, because that remains the layer every other control understands.
Sources
Frequently asked questions
What is the difference between Heidenhain conversational and Fanuc G-code?
Grammar. Klartext writes readable dialogue lines like L X+50 R0 FMAX; Fanuc writes word-address blocks like G00 X50.. Both are typed programs describing motion explicitly.
Is Heidenhain Klartext the same as menu programming like ShopMill or Mazatrol?
No. Klartext is conversational text producing a written program you read line by line, much closer to G-code than to graphical work steps.
Can a Heidenhain control run normal G-code?
Yes, TNC controls offer a DIN/ISO mode alongside Klartext, and CAM systems post to Heidenhain in either format.
What is the best way to learn G-code if I know Heidenhain Klartext?
Map the concepts to their word-address names and drill the vocabulary. A free app like G-Code Sprint quizzes the everyday codes and repeats whichever ones you miss; for a Klartext hand it is pure translation.
G-Code Sprint is a study and practice tool only. Always follow your instructor, employer, machine manual, and shop safety procedures.