Creating User Defined Functions With Cfc - Siemens siprotec 7SA6 User Manual

5.3

Creating User Defined Functions with CFC

General
Run-Time
Properties
7SA6 Manual
C53000-G1176-C133-1
The 7SA6 relay is capable of implementing user defined logic functions which may be
processed by the relay. This CFC feature (Continuous Function Chart) is needed to
process user defined supervision functions and logic conditions (e.g. interlocking
conditions for switching devices) or to process measured values. Interlocking
conditions and command sequences, for example, may be programmed, using pre-
defined function modules, by persons without any specialized software programming
abilities. A total of 21 types of functional modules (FM), with which the desired
functions may be composed, are saved in a library. Detailed explanations are in the
CFC manual, order number E50417–H1176–C098, or in the DIGSI
number E50417–H1176–C097.
The creation of a logical PLC function is performed by means of a personal computer
using application DIGSI
order to create user defined logic functions, the indications and measured values
required by these functions must first be configured in the matrix with CFC as the
source or destination (see Section 5.2).
CFC can be started by double-clicking on &)&. The names of all available CFC charts
will appear. The desired CFC chart for processing can be selected via a double-click
of the mouse. The CFC program will start, and the chart will be displayed. If no chart
is available yet, you can create a new chart via the menu &UHDWH → &)&²&KDUW.
The functions to be implemented in CFC may be divided into four task levels:
• Measured values: This task is processed cyclically every 600 milliseconds
(09B%($5% = measurement value processing) and might become slower if the
device is in pick-up state.
• System logic: Operation is triggered by events (i.e. these functions are processed
for each change of state at one of its inputs). System logic has lower priority than a
protection function and will be suppressed as soon as the relay picks up
(3/&B%($5% = slow PLC processing).
• Protective functions: These functions have the highest priority, and, like the system
logic functions, are event-controlled and processed immediately after a change of
state (3/&B%($5% = fast PLC processing).
• Switchgear Interlocking: This task is triggered by commands. In addition it is
processed cyclically approximately every second. It might becomes slower if device
is in pick-up state (6)6B%($5% = interlocking).
The function to be implemented must be associated to one of these four task levels.
To implement a function from the 6HWWLQJV → &)& menu, activate the menu by
selecting (GLW, and then 5XQ 6HTXHQFH, and then the desired task level (See Figure
5-34).
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4 and transferred via the operator or service interface. In
Configuration
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4 manual, order
5-37