HEIDENHAIN TNC 306 Technical Manual - Manual (Page 304)

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TNC 416/TNC 406/TNC 306 Program creation 3/2000
2.2
Address allocation
2.2.1 Operand directory
Operand Abbreviation Address range
Marker M (Marker) 0 to 3263
Input I (Input) I0 to I31; I128 to I151;
I64 to I126 (PL 400) or up to I127 (PL 410)
Output O (Output) O0 to O30;
O32 to O62(PL 400/PL 410)
Counter C (Counter) Set counter : C0 to C31
Counter-contents: C48 to C79
Release count pulse: C96 to C127
Timer T (Timer) Timer-start: T0 to T47
Timer running: T48 to T95
Byte B (Byte) 0 to 1023 (8 Bit)
Word W (Word) 0 to 1022 (16 Bit)
Double word D (Double word) 0 to 1020 (32 Bit)
Constant K – 2 147 483 647 to + 2 147 483 647
2.2.2 Addressing the word memory
The memory for the operands B (8 bits), W (16 bits), D (32 bits) is only 8 bits wide. Since the
operands can be 8,16 or 32 bits wide, an overlap of the memory areas will occur, which must be
taken into account in addressing the memory.
8 bit
0 7 B0
B1023
B1022
B1021
B1020 D1020 W1020
B1
B2
B3
B4
B5
W0 D0
W2
W4 D4
W1022
..
.
..
.
..
.
..
.
➞ High-Byte for W; Highest-Byte for D
➞ Lowest-Byte for D
➞ Low-Byte for W
In byte addressing every address from 0 to 1023 is accessible. In word addressing, every second
address from 0 to 1022 is accessible and in double word addressing every fourth from 0 to 1020.
The address parameter gives the High byte for a word Address (W) , or the Highest byte for a double
word address (D).
Markers M1000 to M2000 and bytes B0 to B127 are non-volatile, i.e. the contents of this memory
are not lost when the power supply is switched off.