ABB CL Series, Applications Manual

Page: 118 / 428

Display system operation
115
1SVC 440 795 M1100
Program
A program is a sequence of commands which the display
system executes cyclically in RUN mode. A display system
program consists of the necessary device settings, CL-NET,
COM-LINK, password, system settings, a circuit diagram
and/or function blocks and/or visualization screens.
The circuit diagram is that part of the program where the
contacts are connected together. In RUN mode a coil is
switched on and off in accordance with the current flow and
the coil function specified.
Function blocks
Function blocks are program elements with special
functions. Example: Timing relays, time switches, arithmetic
function blocks. Function blocks are elements provided with
or without contacts and coils as required. In RUN mode the
function blocks are processed according to the circuit
diagram and the results are updated accordingly.
Examples:
Timing relay = Function block with contacts and coils
Time switch = Function block with contacts
Visualization screens
Visualisation screens are the sections of programs
containing the display and operator functions.
Relays
Relays are switching devices which are electronically
simulated in the display system. They actuate their contacts
according to their designated function. A relay consists of at
least a coil and a contact.
Contacts
You modify the current flow with the contacts in the circuit
diagram. Contacts such as N/O contacts carry a signal 1
when closed and 0 when open. Every N/O or N/C contact in
the circuit diagram can be defined as either a N/O contact or
a N/C contact.