HEIDENHAIN iTNC 530 (34049x-08) ISO programming - Manual (Page 276)

276 Programming: Q parameters
9.1 Pr
inciple and o
v
erview
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, meaning that up to nine digits plus
the algebraic sign are permitted. You can set the decimal point at any
position. Internally, the TNC can calculate up to a range of 57 bits
before and 7 bits after the decimal point (32-bit data width
corresponds to a decimal value of 4 294 967 296).
You can assign a maximum of 254 characters to QS parameters.
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 308).
If you are using the parameters Q60 to Q99 in encoded
OEM cycles, use MP7251 to define whether the
parameters are only to be used locally in the OEM cycles
(.CYC file), or can be used globally for all programs.
With MP7300 you specify whether the TNC should reset
Q parameters at the end of the program, or if the values
should be saved. Make sure that this setting does not
have any effect on your Q parameter programs!
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.