Heidenhain TNC 640: Tables & System Data

Almost everything interesting on a TNC 640 lives in a table: tool data, magazine pockets, presets, datums, compensation values, and any custom data you care to store. This reference maps the table landscape, then covers the four ways an NC program reads and writes it — FN 26/27/28 for freely definable tables, TABDATA for the active tool/compensation tables, SQL statements for everything at speed, and FN 18: SYSREAD for live system data — plus FN 16: F-PRINT for getting results out as formatted reports. Verified against the TNC 640 manuals (Klartext 34059x-11, Setup 34059x-18); numbers differ on other Heidenhain series.

The Table Landscape

Machine-wide tables live in TNC:\table\. Table and column names must start with a letter and must not contain arithmetic operators (SQL chokes on them).

TOOL.T — the columns worth knowing

Pocket table key columns: P pocket number, T tool number, RSV reservation (box magazines), ST special tool, F fixed pocket, L locked pocket, DOC comment from TOOL.T, PLC, PTYP, and LOCKED_ABOVE/BELOW/LEFT/RIGHT for box magazines. Preset table: PRESET.PR is editable only in Manual Operation / El. Handwheel after pressing CHANGE PRESET; new rows can only be appended at the end; write-protection per row is available. Touch-probe cycles 400–405, 408–419 and 14xx can write to it directly (see the probing article). Never delete line 0 of TOOL.T — the manual warns this permanently destroys the table structure.

FN 26 / 27 / 28 — Freely Definable Tables

Create a .TAB file in the file manager (the control offers stored templates; save your own under TNC:\system\proto), then shape it with the structure editor. Column types include TEXT, DEC, INT, LENGTH (converted in inch programs), FEED, FLOAT, BOOL, TSTAMP, UPTEXT, PATHNAME. Text-type columns can only be read or written via QS parameters — even if a cell happens to contain a number.

53 Q5 = 3.75
54 Q6 = -5
55 Q7 = 7.5
56 FN 27: TABWRITE 5/"RADIUS,DEPTH,D" = Q5   ; writes Q5/Q6/Q7 into row 5

56 FN 28: TABREAD Q10 = 6/"X,Y,D"            ; row 6 -> Q10, Q11, Q12
57 FN 28: TABREAD QS1 = 6/"DOC"              ; text column -> QS1

Row count of the open table is readable with FN 18: SYSREAD ... ID56 NR4 — handy for loops that walk a table.

TABDATA — Direct Access to the Active Tables

The TABDATA functions (SPEC FCT → PROGRAM FUNCTIONS → TABDATA) hit the currently active tables without an FN 26 open/close dance: the tool table *.t (read-only) and the compensation tables *.tco and *.wco (read and write). Values convert automatically between mm and inch to match your program — unlike FN 18, which is always metric. Write access works only during program run; writes during simulation or block scan have no effect.

Compensation tables must be activated first with SEL CORR-TABLE TCS "TNC:\table\corr.tco", and a row is applied with FUNCTION CORRDATA TCS + row number (reset via FUNCTION CORRDATA RESET). An active .tco row overwrites DL/DR/DR2 from the TOOL CALL block; .wco acts as a shift in the working-plane coordinate system. Changed values take effect only when the compensation is activated again.

SQL Statements

For table work beyond single cells, the control exposes an SQL-like transaction interface — and HEIDENHAIN explicitly recommends SQL over FN 26–28 for speed. Programming SQL commands requires code number 555343. All SQL reads/writes are in metric units regardless of table or program settings — convert before positioning with a read value in an inch program. Every transaction, even read-only, must be concluded with COMMIT or ROLLBACK to release locks.

11 SQL BIND Q881 "Tab_Example.Position_Nr"
12 SQL BIND Q882 "Tab_Example.Measure_X"
13 SQL BIND Q883 "Tab_Example.Measure_Y"
14 SQL BIND Q884 "Tab_Example.Measure_Z"
...
91 SQL BIND Q881                       ; remove bindings when done

FN 18: SYSREAD — System Data

System data are addressed by group ID, number NR, and optional index IDX. Values always come back metric, regardless of the program’s unit (use TABDATA READ instead if you want automatic conversion from the tool table). Reads that must reflect real time should be preceded by FN 20: WAIT FOR SYNC, which halts the look-ahead:

32 FN 20: WAIT FOR SYNC
33 FN 18: SYSREAD Q1 = ID270 NR1 IDX1      ; current X position, input system

55 FN 18: SYSREAD Q25 = ID210 NR4 IDX3     ; active scaling factor, Z axis

The full list fills 40 pages of the Klartext manual (chapter 17); these are the groups a machinist macro actually touches:

String-valued system data go through SYSSTR instead (ID10010 program paths, ID10025 channel name, ID10060 tool name from TOOL CALL, ID10321 date/time in 16 formats, ID10350/10353 probe types, ID10630 NC software version). Machine parameters are read with CFGREAD — see the Klartext & Q-Parameters article.

FN 16: F-PRINT — Formatted Output

FN 16 turns Q-parameter contents into measurement reports, pop-up messages, or printer output. Two pieces: a mask file (extension .A, created in the text editor) that defines the layout, and the FN 16: F-PRINT call naming mask and target. Mask syntax:

; Mask file TNC:\MASKE\MASKE1.A
"MEASURING LOG OF IMPELLER CENTER OF GRAVITY";
"DATUM: %02d.%02d.%04d",DAY,MONTH,YEAR4;
"TIME: %02d:%02d:%02d",HOUR,MIN,SEC;
"X1 = %9.3F", Q31;
"Y1 = %9.3F", Q32;
"Z1 = %9.3F", Q33;
L_ENGLISH;
"Remember the tool length";

; In the NC program:
96 FN 16: F-PRINT TNC:\MASKE\MASKE1.A/ TNC:\PROT1.TXT

Output targets: a file on the control (max. 20 KB; the log-file extension picks the type — .TXT, .A, .XLS, .HTML), SCREEN: for a pop-up window (close with CE, or programmatically with target SCLR:), an external path (e.g. PC325:\LOG\PRO1.TXT), or Printer:\. Repeated output to the same file appends unless the mask says M_TRUNCATE. Both mask and log paths may come from QS parameters (:'QS1' syntax), and relative paths work. Default output directories are set under MOD code 123 → fn16DefaultPath / fn16DefaultPathSim.

PLC Transfer: FN 19 / FN 29 / FN 37

For completeness: FN 19: PLC hands two numeric values/Q parameters to the PLC, FN 29: PLC hands over up to eight, and FN 37: EXPORT exposes local QL/QS parameters from your own OEM-style cycles to the calling program. All three carry the same manual warning: PLC access is password-protected OEM territory — use only in consultation with HEIDENHAIN or your machine builder. The everyday alternative for pushing data off the machine is FN 38: SEND (log/StateMonitor output, no PLC involvement): FN 38: SEND /"Q-Parameter Q1: %f Q23: %f" / +Q1 / +Q23.

References

• HEIDENHAIN, TNC 640 Klartext Programming User’s Manual, NC software 34059x-11, 01/2021, ID 892903-29 (FN functions, TABDATA, SQL, system data chapter 17).
• HEIDENHAIN, TNC 640 Setup, Testing and Running NC Programs User’s Manual, NC software 34059x-18, 10/2023, ID 1261174-25 (tool/pocket/preset tables, file types).