2.5.4 Machine Data For Operation; Speeds - Siemens SIMATIC S5 Manual

tripping of a hardware limit switch is, however, only recognized when the axis is moving or
should move in the direction of the activated switch.
When machine data are transferred to the module, the assignment of parameters for the hard-
ware limit switches is checked. The IP247 can only detect incorrect parameter assignment when
neither of the hardware limit switches is active when the machine data are input. If a rotary axis
has been selected, the digital inputs for hardware limit switches are also evaluated, If, however,
no limit switches are connected, the polarity must be set to "normally open" (COM247: "pos", PC
interface ''O").

2.5.4 Machine Data for Operation

Regardless of whether you operate your axis as a linear or rotary axis, the IP247 allows the fol-
lowing dimensional units to be used:
metric system with a basic unit of 0.001 mm,
inches with a basic unit of 0.0001 inches and
degrees with a basic unit of 0.001 degrees.
The basic units are the smallest values permitted in machine data, machining programs and com-
mand inputs. All positions, speeds and the resolution relate to the dimensional unit selected for
the axis.
2.5.4.2

Speeds

Machine Data and their Structure
2-21