Inside the display system
372
1SVC 440 795 M1100
Effects on the creation of the circuit diagram
The display system evaluates the circuit diagram in these six
segments in succession. You should therefore remember two
points when you create your circuit diagrams:
• The changeover of a relay coil does not change the switching
state of an associated contact until the next cycle starts.
• Always wire forward or from top to bottom. Never work
backwards.
Example: Self-latching with own contact
Start condition:
Inputs I1 and I2 are switched on.
Q1 is switched off.
This is the circuit diagram of a self-latching circuit. If I1 and
I2 are closed, the switching state of relay coil
Ä Q 01 is
“latched” via contact
Q01.
•
1st cycle:
Inputs I1 and I2 are switched on. Coil Q1 picks up.
• Contact Q 01 remains switched off since the display
system evaluates from left to right. The first coil field was
already passed when the display system refreshes the
output image in the 6th segment.
• 2nd cycle: The self-latching now becomes active. The
display system has transferred the coil states at the end of
the first cycle to contact Q 01.
Example: Do not wire backwards
This example is shown in section “Creating and modifying
connections”, page 134. It was used there to illustrate how
NOT to do it.
In the third rung, the display system finds a connection to the
second rung in which the first contact field is empty. The
output relay is not switched.
When wiring more than four contacts in series, use one of
the marker relays.
Figure: 186: Circuit diagram with M 01 marker relay
I 01--u-I 02-..--Ä Q 01
Q 01--k
I 01----Q 04--o
z------k
h--------I 03--
L: 8 C:2 B:7688
I 01----Q 04----i 03----I 05---Ä M 01
I 02----I 04----M 01-----------Ä Q 02
To Next Page
Loading...
Need help?
General
