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SIF5600 - Manual - 03 - 2008
the SIF5600 relay uses a DSP processor operating at 40 MHz; it performs all the processing on the
analogue signals and furthermore coordinates management of the input-output signals (relay com-
mand, LeDs, display, keyboard management and serial communication).
the input currents are sampled at a frequency of 32 samples per period by means of a dual conver-
sion system which allows the attainment of information pertaining to polarity and amplitude with high
resolution. the measurement criterion allows precise measurement of even those signals having a
unidirectional component, such as transient currents with overlapping exponential, which typically
appear during faults.
the circuit board also houses the output relays with the corresponding command and control cir-
cuits, communication circuits, buttons, LcD display, LeDs and the key switch.
4.2 SOFtWAre
the program which handles operation of the SIF5600 relay is made up of three fundamental elements
shown in the following block diagram.
Kernel
the kernel represents the nucleus of the system: it includes the processing functions closest to the
electronic circuits; particularly the algorithms providing for the generation of the synchronisms (tim-
ers) for sampling the analogue signals and numerical processing.
the software is structured with interrupts operating with various priority levels in a non “pre-emp-
tive” task system. By means of Discrete Fourier transform calculation, based on 32 samples/period,
information is deduced in relation to the amplitude and phase of all the current measurements; these
are constantly updated and at the disposal of all the protection and control application algorithms.
In addition, the kernel manages a service communication protocol known as Basic Protocol (BP).
Drivers
the driver library contains all the specialised modules for the command and control functions which
make up the connection ring between the kernel and the application. examples of drivers include the
Modbus communication and LcD display modules.
Application
the application contains all the elements which carry out the protection and control functions.
the main modules are:
- diagnostic function,
- input management (logical inputs and block signal),
- protective functions,
- event recording,
- output management (output relays, LeDs and block signals).
each element (Kernel, Drivers and Application) may, in turn, be split into modules:
Base protocol (kernel)
the module known as the Basic Protocol (BP) manages the service communication between the
kernel and the other modules through the communication buses:
- direct for internal functional call,
- SPI over synchronous serial,
- ScI over asynchronous serial.
the activities which may be performed by means of BP include:
- measurement configuration ,
- measurement reading,
- measurement enabling.
Calibration (kernel)
calibration is performed using the base protocol functions for coordinating the calibration and test-
ing stages with the automatic testing equipement (Ate).
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