Siemens SIMATIC S5-100U System Manual page 447

S5-100U
Reference
signal
Reference pulse
of the sensor
Reference
signal
Reference pulse
of the sensor
Synchronization
Sync. bit
Figure 15-19a. Synchronization (SYNC Bit 0 -->1)
during a Reversal of Direction before Reaching the Reference Pulse in a
Positive Direction
Example: Transporting objects from point A to point B on a conveyor belt.
A rotary position encoder is used, together with a BERO proximity switch as reference
transmitter. The conveyor belt is marked at a definite point. As soon as this mark
comes within the range of the BERO, the BERO produces a reference signal.
Following the reference point approach, the enable input is set via a digital output module.
PS CPU DQ
Enable input
Reference input
Figure 15-20. Schematic of a Reference Point Approach Operation
EWA 4NEB 812 6120-02b
Positive direction of traverse
Change of direction
Operation range
Rotary position
of reference
encoder
transmitter
Traversing path
Traversing range
Change of direction
No synchronization
15-19b. No Synchronization
Conveyor belt
Counting-up
direction
Mark
BERO as refer-
ence transmitter
Function Modules
15-33