Klartext suffers from a description problem: people who have not used it assume it is a menu system, conversational in the guided-forms sense, and it is not. Heidenhain’s native format is a real programming language whose design goal was human readability, typed code, edited as text, where a linear move reads like a labeled sentence and a cycle’s parameters carry names instead of letter positions. That makes the comparison genuinely two languages on one control, and the decision between them more interesting than the usual conversational-versus-code split.
Why Heidenhain built a second language at all
The design bet dates to an era when programs were written at the control by machinists, not posted from CAM by programmers, and Heidenhain bet that a language reading like labeled sentences would beat letter codes for that life: fewer reference lookups, fewer transposition errors, programs reviewable by anyone on the floor. The bet paid in its home market, European die-mold and contract machining, where at-control programming and editing remained central long after other sectors went CAM-first, and it explains the format’s character: Klartext optimizes for the human at the panel, DIN/ISO for compatibility with everything else, and the control carries both because its customers genuinely need both lives.
Placing the two languages
| Property | Klartext | DIN/ISO mode |
|---|---|---|
| What it is | Heidenhain’s native plain-language program format | Standard G-code on the same control |
| A move looks like | A labeled line: motion type, named coordinates, feed | G01 X.. Y.. F.. |
| Written by | Machinists at the control; CAM posts targeting Klartext | CAM posts; anyone from the Fanuc-shaped world |
| Where it dominates | European die-mold and job shops, at-control work | Posted work, mixed fleets, inherited programs |
| Converts to the other? | No automatic conversion: choose per program | No: same answer from the other side |
The no-conversion row carries the workflow weight: like the Mazatrol-versus-EIA split, the two formats coexist per program rather than translating, so shops standardize by job type, and the decision logic of the conversational family applies with Klartext in the native-format seat.
What Klartext’s readability actually buys, and costs
The readable surface is real: a machinist’s first week on a Klartext control involves dramatically less decoding than the G-code equivalent, because the program says words where ISO says letters. The honest accounting adds the costs. Readability is local to the ecosystem, Klartext fluency reads nothing outside Heidenhain’s world, while ISO fluency reads most of the planet’s machines. And the concepts underneath, coordinates, compensation, cycle logic, tool management, are identical in both languages: Klartext’s friendly syntax does not waive the conceptual curriculum, it just renders it in longer words. The machinist who knows why comp needs a lead-in move writes it correctly in either language; the one who does not is equally stuck in both, more comfortably in Klartext.
For working in the ISO mode itself, including who chooses it and the simulator situation, the Heidenhain ISO programming page carries the detail; the 828D comparison tells the neighboring European-control story, where Siemens answered the same design question differently.
The transfer math for careers
Heidenhain shops, concentrated in European tooling and die-mold work, hire for Klartext and teach it on arrival; the broader market runs Fanuc-shaped ISO. The portable investment is therefore unchanged: the conceptual core plus standard G-code fluency travels everywhere including into a Klartext shop, where it converts to the native syntax in weeks because the concepts arrive pre-built, exactly the pattern of every conversational transition run in reverse. The free 60-second rounds on the G-code practice page build that core, and on a Heidenhain floor the payoff is specific: the ISO mode reads like home, and Klartext reads like the same machine speaking slower and more clearly, which is precisely what its designers intended.
Sources
Frequently asked questions
What is the difference between Heidenhain Klartext and DIN G-code?
Two languages on one control: Klartext is Heidenhain’s native plain-language format, typed dialogue code with readable words, while DIN/ISO mode is standard G-code. They do not auto-convert; shops choose per program.
Is Klartext easier to learn than G-code?
Its surface is friendlier and the concepts underneath are identical: the same coordinates, compensation, and cycle logic wearing different syntax. The honest comparison is two notations, not two difficulty levels.
Do Heidenhain machines run normal G-code programs?
In DIN/ISO mode, yes, with standard dialect caveats: the core reads as expected, the edges differ from Fanuc-family habits, and inherited programs get the documentation check.
Which should I learn first if my shop runs Heidenhain?
Concepts first, they power both languages, then your shop’s dominant format, usually Klartext at the control. The free G-Code Sprint app builds the concept-and-code core in 60-second rounds.