Siemens siprotec SJ62 User Manual page 24

Microcomputer
System
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
Voltage inputs can either be used to measure the three phase-to-ground voltages, or
two phase-to-phase voltages and the displacement voltage (V
sible to connect two phase-to-phase voltages in open-delta connection.
The four voltage transformers of 7SJ64 can either be applied for the input of 3 phase-
to-ground voltages, one displacement voltage (V
synchronizing function.
The analog input quantities are passed on to the input amplifiers (IA). The input am-
plifier IA stage provides high-resistance terminations for the analog input quantities. It
consists of filters that are optimized for measured-value processing with regard to
bandwidth and processing speed.
The analog-to-digital (AD) stage consists of a multiplexor, an analog-to-digital (A/D)
converter and of memory components for the transmission of digital signals to the mi-
crocomputer system.
Figure 1-2 Hardware structure of the numerical multi-functional device 7SJ64
Apart from processing the measured values, the microcomputer system (μC) also ex-
ecutes the actual protection and control functions. They especially include:
• Filtering and preparation of the measured quantities
• Continuous monitoring of the measured quantities
1.1 Overall Operation
voltage). It is also pos-
N
voltage) or a further voltage for the
N
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