HEIDENHAIN TNC 128 (77184x-01) - Manual (Page 181)

HEIDENHAIN TNC 128 181
8.1 Pr
inciple and o
v
erview
QS parameters (the S stands for string) are also available on the TNC
and enable you to process texts. In principle, the same ranges are
available for QS parameters as for Q parameters (see table above).
Programming notes
You can mix Q parameters and fixed numerical values within a
program.
Q parameters can be assigned numerical values between
-999 999 999 and +999 999 999. The input range is limited to 15 digits,
of which up to 9 may be before the decimal point. Internally the TNC
calculates numbers up to a value of 10
10
.
You can assign a maximum of 254 characters to QS parameters.
Freely usable QL parameters, only effective
locally (within a program) QL0 to QL499
Freely usable QR parameters that are nonvolatile,
i.e. they remain in effect even after a power
interruption QR0 to QR499
Note that for the QS parameters the QS100 to QS199 range
is reserved for internal texts.
Local parameters QL are only effective within the
respective program, and are not applied as part of program
calls or macros.
Meaning Range
Some Q and QS parameters are always assigned the
same data by the TNC. For example, Q108 is always
assigned the current tool radius (see "Preassigned Q
parameters", page 242).
The TNC saves numerical values internally in a binary
number format (standard IEEE 754). Due to this
standardized format some decimal numbers do not have
an exact binary representation (round-off error). Keep this
in mind especially when you use calculated Q-parameter
contents for jump commands or positioning movements.