HEIDENHAIN TNC 306 Technical Manual - Manual (Page 341)

3/2000
TNC 416/TNC 406/TNC 306 Commands 7-51
3.3.5 EXCLUSIVE OR (XO)
Abbreviation for the PLC-Editor: XO (EXCLUSIVE OR)
Logic Byte/Word Double Constant
Execution time [µs] 1.6 1.6/1.6 2.4 2.0
Number of bytes 6 6 6 8
Logic execution with the EXCLUSIVE OR 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 the command functions as an L command, i.e. the logic state 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 L 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. The result of the operation is stored in the Logic
Accumulator.
Example:
Inputs I4 and I5 are to be gated with EXCLUSIVE OR and the result assigned to Output O2.
Initial state: Input I4 = 1
Input I5 = 1
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 I4 ... x x x x x x 1 x x x x x x x 1
2 XO I5 ... x x x x x x 0 x x x x x x x 1
3 = O2 ... x x x x x x 0 x x x x x x x 0
Line 1: The operand contents are loaded into the Accumulator.
Line 2: The contents of the Logic Accumulator and input I5 are gated with EXCLUSIVE OR.
Line 3: The gating result is assigned to Output O2.