Heidenhain TNC 320: Tables & System Data

On a TNC everything that matters at run time lives in a table: tools, pockets, presets, datums, probe data, compensations. The control gives an NC program four doors into that data — FN 26/27/28 for your own .TAB files, TABDATA for the active tool/compensation/preset tables, SQL for everything at full speed, and FN 18: SYSREAD for live system data via ID/NR/IDX numbers. FN 16: F-PRINT then gets results out as a formatted log. This page maps all of it for the TNC 320.

The Table Landscape

Standard tables live in TNC:\table\. Table and column names must start with a letter and must not contain arithmetic operators like + — SQL chokes on them. All tables can be viewed as list or form (Screen Layout key), and the code number 555343 unlocks the EDIT FORMAT structure editor.

FN 26/27/28 — Your Own Tables

The classic trio for .TAB files. Only one table can be open at a time; a new FN 26 closes the previous one. Within one block you can address several columns but only one row; multi-column transfers use consecutive variables of the same type.

TABDATA — the Active Tables Without SQL

The TABDATA functions (SPEC FCT → PROGRAM FUNCTIONS) address the currently active tables by column name and row key: tool table *.t (read-only), compensation tables *.tco/*.wco and preset table *.pr (read + write). Two properties make them the friendly option: values are automatically converted between mm and inch to match your NC program (FN 18 always returns metric), and write access only ever happens during program run — in simulation or block scan a write is a no-op. A typical use is pushing a probe-measured wear value into an active compensation table:

12 SEL CORR-TABLE TCS "TNC:\table\corr.tco"         ; activate compensation table
13 TABDATA READ  Q1 = CORR-TCS COLUMN "DR" KEY "5"  ; row 5, column DR -> Q1
14 TABDATA WRITE CORR-TCS COLUMN "DR" KEY "3" = Q1  ; write Q1 into row 3
15 TABDATA ADD   CORR-TCS COLUMN "DR" KEY "3" = Q1  ; or add Q1 to the existing value

SQL Statements

For anything bigger than single cells, the TNC 320 has a real SQL server — HEIDENHAIN explicitly recommends it over FN 26–28 for speed. Programming SQL requires the code number 555343. It is transaction-based: every transaction you open must be closed with SQL COMMIT or SQL ROLLBACK, even a pure read, or locks and resources stay held. Two warnings from the manual: SQL always works in metric regardless of program units, and SQL executed during simulation really writes to tables — guard with FN 18: SYSREAD ID992 NR16.

WHERE conditions: ==, !=/<>, <, <=, >, >=, IS NULL, IS NOT NULL, combined with AND/OR; compare against a Q parameter with WHERE Position_Nr==:'Q11' (Q/QL/QR get rounded to integers — use QS for exact text). The manual's complete read example:

0 BEGIN PGM SQL_READ_WMAT MM
1 SQL Q1800 "CREATE SYNONYM my_table FOR 'TNC:\table\WMAT.TAB'"  ; short name for path
2 SQL BIND QS1800 "my_table.WMAT"           ; bind QS1800 to column WMAT
3 SQL QL1 "SELECT WMAT FROM my_table WHERE NR==3"                ; open transaction, HANDLE -> QL1
4 SQL FETCH Q1900 HANDLE QL1                ; read row 0 into QS1800 (Q1900: 0=OK)
5 SQL ROLLBACK Q1900 HANDLE QL1             ; close the (read-only) transaction
6 SQL BIND QS1800                           ; release binding
7 SQL Q1 "DROP SYNONYM my_table"            ; clean up
8 END PGM SQL_READ_WMAT MM

FN 18: SYSREAD — System Data by ID/NR/IDX

Numeric system data is addressed by group ID, number NR, and an optional index IDX (often an axis 1–9 = X, Y, Z, A, B, C, U, V, W). Results are always metric. Because look-ahead pre-calculates blocks, sync the read with FN 20: WAIT FOR SYNC first when you need a live value; string system data goes through SYSSTR into a QS parameter instead.

11 FN 20: WAIT FOR SYNC                        ; stop look-ahead so the value is current
12 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
11 QS25 = SYSSTR ( ID10950 NR1 )               ; current tool name (string)

The groups you will actually use, verified from the TNC 320 FN 18 list:

FN 16: F-PRINT — Formatted Output

FN 16 renders a mask file (a text file, extension .A, created in PGM MGT) into an output file, a screen pop-up, a USB/network target, or a PostScript printer. Format lines are case-sensitive; each ends with ; and * starts a comment line. Output file max 20 kB; the extension of the target file sets its type (.TXT, .A, .XLS, .HTML).

Mask file and call, straight from the manual — the output lands in TNC:\PROT1.TXT:

* MASKE1.A -- the format mask
"MEASURING LOG OF IMPELLER CENTER OF GRAVITY";
"DATE: %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;
M_CLOSE;

; in the NC program:
96 FN 16: F-PRINT TNC:\MASKE\MASKE1.A / TNC:\PROT1.TXT
11 FN 16: F-PRINT TNC:\MASKE\MASKE1.A / SCREEN:      ; pop-up on the control screen
96 FN 16: F-PRINT / SCLR:                            ; close the pop-up

Repeated output to the same target appends by default — use M_TRUNCATE or M_CLOSE to overwrite. Default output paths can be preset in machine parameters fn16DefaultPath/fn16DefaultPathSim (no. 102202/102203), but a path in the FN 16 block wins. Paths (source and target) may come from QS parameters: :'QS1'.

FN 19/20/29/37/38 — PLC and the Outside World

FN 19: PLC (two values) and FN 29: PLC (up to eight values) transfer numbers to the PLC, and FN 37: EXPORT exposes local QL/QS parameters to a calling program when you build your own cycles. All three carry a collision NOTICE in the manual and are meant for HEIDENHAIN, the machine manufacturer, or third-party cycle authors — not for day-to-day part programs. FN 20: WAIT FOR synchronizes NC and PLC; its everyday use is FN 20: WAIT FOR SYNC before an FN 18 read, as shown above. FN 38: SEND writes fixed or variable text to the log or over TCP/IP to an external application such as StateMonitor (up to seven Q values per message, C-style placeholders):

FN 38: SEND /"Q-Parameter Q1: %f Q23: %f" / +Q1 / +Q23
FN 38: SEND /"JOB:1234_STEP:1_START"          ; StateMonitor job tracking
FN 38: SEND /"JOB:1234_STEP:1_OK_I:1"         ; report one good part (incremental)

References

• HEIDENHAIN, TNC 320 Klartext Programming User's Manual, NC software 77185x-18, 10/2023, ID 1096950-25 (Q parameters, FN functions, SQL, freely definable tables, FN 18 list).
• HEIDENHAIN, TNC 320 User's Manual for Setup, Testing and Running NC Programs, NC software 77185x-18, 10/2023, ID 1263173-21 (tool table, pocket table, touch probe table, preset management).