HEIDENHAIN TNC 306 Technical Manual - Manual (Page 343)

3/2000
TNC 416/TNC 406/TNC 306 Commands 7-53
3.3.6 EXCLUSIVE OR NOT (XON) XON
Abbreviation for the PLC-Editor: XON (EXCLUSIVE OR NOT)
Logic Byte/Word Double Constant
Execution time [µs] 2.0 2.0 3.0 2.6
Number of bytes 8 8 8 10
Logic execution with the EXCLUSIVE OR NOT command
Operands: M, I, O, T, C
Operation:
This command functions in different ways according to its position in the program:
a) At the start of a logic chain this command functions as a LN command, i.e. the complement of the
operand is loaded into the Logic Accumulator. This is to ensure compatibility with the TNC 355
control which did not have the special LN command. In PLC programs for the TNC 306 a logic
chain should always be started with a load command (see L, LN, L–).
b) Within a logic chain the contents of the Logic Accumulator and the logic state of the operand (M,
I, O, T, C) are gated with EXCLUSIVE OR NOT. The result of the operation is stored in the Logic
Accumulator.
Example:
Input I4 and Marker M500 are to be gated with EXCLUSIVE OR NOT and the result assigned to
Output O2.
Initial state: Input I4 = 0
Marker M500 = 0
Output O2 = ?
Line Instruction Accumulator contents Operand contents
Bit 31 . . . 7 0
... x x x x x x X x x x x x x x
1 L M500 ... x x x x x x 0 x x x x x x x 0
2 XON I4 ... x x x x x x 1 x x x x x x x 0
3 = O2 ... x x x x x x 1 x x x x x x x 1
Line 1: The operand contents are loaded into the Accumulator.
Line 2: The contents of the Logic Accumulator and input I4 are gated with
EXCLUSIVE OR NOT.
Line 3: The gating result is assigned to Output O2.