Areva KITZ 101 - Communication ports

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9.6 Communication ports
9.6.1 K-Bus port
Language: COURIER
Transmission: Synchronous - RS485 voltage levels
Transmission Coding: Biphase space
(Differential Manchester)
Frame Format: HDLC
Baud Rate: 64k/bit per second
K-Bus Cable: Screened twisted pair
K-Bus cable length: 1000m of cable (maximum)
K-Bus Loading: 32 units (multi-drop system)
Isolation: 2kV rms for one minute
Voltage signals
(Based on RS485 differential voltage level):
Unloaded driver differential output: ±5V
Receiver input sensitivity: ±200mV
Figure 4: Circuit diagram of K-Bus electrical interface.
TxD
Tx/Rx
RxD
RS485
Driver/Receiver
Pair
1:1
Isolating
Transformer
15V
Transient
Suppressor
Ground
7V5
7V5
Interference
Suppressor
Zener diodes