FUNCTION CHARACTERISTICS
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NG10 - Manual - 04 - 2022
Power supply board
All the components necessary for conversion and stabilization functions are present.
Two versions are envisaged suited to the input ranges 24...48 V and 115...230 V.
The circuit provides stabilized voltages of +10 V and -10 V, required for the analogue measurement,
+24 V for relays and +5 V for supplying the digital circuits.
The circuit board additionally comprises:
INPUT CIRCUITS:
• Two binary input circuits,
• One block input circuit (BLIN1).
The logical input circuits and the block circuits include photo-couplers which provide for galvanic
separation.
OUTPUT CIRCUITS:
• One block output circuit (BLOUT 1),
• Six output relays (k1...K6).
CPU board
This circuit board contains all the circuits necessary for performing the analogue and digital pro-
cessing of the signals.
Analog processing
The following are envisaged:
• Anti aliasing filter circuits,
• Amplifier circuits for conditioning the input signals,
• Reference voltage adjustment circuits for the measurement A/D converter.
The Pro-n relays use a DSP processor operating at 40 MHz; it performs all the processing on the
analogue signals and furthermore coordinates management of the TX-RX signals to the CPU.
The input currents are sampled at a frequency of 24 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.
CPU
A 32 bit CPU is provided.
The following are envisaged:
• Real Time Clock circuits with oscillator and super capacitor,
• USB communication port,
• RS485 communication port,
• Thybus communication circuits for external modules and MMI board,
• Network communication circuits (optional Ethernet).
Memories:
• SRam: high speed static memory, used for data and cache,
• Flash memory: used for fw storage and upgrade,
• EEprom memory: used for calibration data storage,
• Dual port Ram for data transfer between CPU and DSP.
Input board
• Three CTs committed for phase currents acquisition side H
• Three CTs committed for phase currents acquisition side L
• One CT committed for residual current acquisition side 1
• One CT committed for residual current acquisition side 2
The input circuits are suitable for 1 A or 5 A external CTs
[1]
MMI (keyboard, LED and display)
The MMI module (Man Machine Interface) includes:
• An eight keys 8 keyboard,
• a backlight LCD display,
• Eight signalling LEDs,
The removable plug allows separation of the MMI module for free access to the CPU board when
DIP-switch setting is required.
Note 1 The phase and residual nominal currents must be adjusted by means dip-switch.
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