Toshiba GRD150 Series Instruction Manual page 126

The hardware block diagram of GRD150 is shown in Figure 3.1.3.
VCT
Current
- CT
x 4 or 5
Voltage
- VT
x 3 or 4
Local PC
Transformer Module
The transformer module (VCT) insulates between the internal and external circuits through an
auxiliary transformer and transforms the magnitude of AC input signals to suit the electronic
circuits. The AC input signals are as follows:
• three-phase currents (I a , I b and I c )
• residual current (I o ) and zero-sequence current for models 200 and 400 series
• three-phase voltages (V a , V b and V c )
• residual voltage (V 0 ) for model 100 and 200 series, or phase voltage or phase-to-phase
voltage for synchronism check of model 300 and 400 series
VCT SPMM
IO1
Figure 3.1.2 Hardware structure
SPMM
- Analog filter
- Multiplexer
- A/D converter
- MPU
- RAM, ROM
- Communication
control
HMI
- LCD
- LED
- Operation key
- RS232C I/F
Figure 3.1.3 Hardware Block Diagram
⎯ ⎯
125
IO2 IO3 IO4
IO1
- DC/DC
converter
- Binary input
- Binary output
(trip)
- Binary output
(signal)
- RS485
IO2 – IO4
- Binary input
- Binary output
(signal)
6 F 2 S 0 8 4 2
DC supply
Input
Output
Remote PC