Siemens SIMATIC S5 Manual page 221

Sample Applications and Programming Aids
Process
Synchronous operation is controlled as follows:
• Two light barriers (L1 and L2) are arranged so that they are side by side and at a right angle to
the conveyor belt's transport direction. The light barriers are connected to the IP 265's 24 V
inputs, and implement "GATE" functionality for an up/down counter in the IP 265.
The paper or cardboard strip is adjusted as follows:
• A counter is loaded for each new measurement with a count value (CV=100). If the front edge
of a strip triggers one of the light barriers, a clock-pulse generator generates a 64 kHz frequency
at the counting input (whether at the CU or the CD input depends on which barrier was
triggered). Counting is halted when the second light barrier is triggered.
• The IP 265 forwards the count to the CPU as output parameter, and the CPU user program
postprocesses this count to adjust the transport speed of the relevant strip. The number of
pulses counted is one means of ascertaining the amount of deviation. A comparison with the
count shows which strip was too fast or too slow.
• The CPU user program drives an auxiliary motor via an analog output module to adjust the
transport speed.
Load on the IP 265 interfaces
Control word
Status word
Output
parameters (OPs):
QW 66, Q 68.0
: Interface areas used
in the sample application
Figure 13-5. IP 265 Interfaces Used in the Sample Application:
13-8
IP 265
IP 265
IPs
program
OPs
"Synchronizing a Paper Feeder"
24 V inputs (DIs):
I 0.0, I 0.1
DIs
I/Os
user
DQs
24 V outputs (DQs):
Q 0.0
IP 265
EWA 4NEB 812 6130-02a