Siemens SIMATIC S5-90U System Manual page 526

Function Modules
Besides purely traversing movements, other operating modes allow offset generation of axis
coordinates or drift compensation in the system. In addition, the IP 266 offers operating modes to
read data such as positioning actual value or residual traversing distances.
In order to use the IP 266 in an automatic manufacturing process, it is possible to combine individual
traversing applications, positioning corrections, offsets or dwell times in a "traversing program".
These traversing programs can be called up via two special operating modes and processed auto-
matically or semi-automatically.
Such a traversing program can be created by using the "learning capable" "Teach-in-mode" for
positioning applications. The information from single positioning applications can be stored at the end
of an operation in a traversing program.
Positioning
For the positioning operation, the IP 266 calculates the setpoint from the selected end data and
velocity data in conjunction with the programmed machine data. The actual value follows the
selection. The deviation (following error) which occurs reaches a constant value after the short
start-up phase and must reach zero at the end of the positioning operation.
S
(t)
S
Figure 16-29. Course of a Following Error during a Positioning Operation
16-58
s
a
b
s = const
S5-90U/S5-95U
a = Setpoint function
b = Actual value function
S = Following error
t
t
EWA 4NEB 812 6115-02b