Simrad V5035, Operator And Installation Manual

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Appendix A | V5035 Operator and Installation Manual
Bidirectional Data Ports
The schematic of bidirectional data port is shown in Figure A2. The
schematics includes an isolated full duplex RS-485 transceiver IC
(Texas Instrument ISO3080) which is used as the main component
to handle both data input and output from external data source.
The transceiver IC is isolated from external input. To avoid signal
reflection, the transceiver IC has an optional built-in 120Ω loop
termination, which is selectable by the dip-switch on the junction
box and the switch should be set to on position when connecting
external data source with long cable. All bidirectional data ports are
isolated from one another and are also isolated from internal power
supply. The transceiver internal power supply is fully isolated from
the external power supply.
3V3
V5T
3V3
Cable
120
RX_A
TGND
Junction Box
Data
Input
RX_B
TX_B
TX_A
TGND
Data
Output
System Ground
Rx
Tx
To/From
System
Isolated
Isolated Ground
10
10
100K
100K
Main Unit
10K
DE
RX_A
RX_B
TX_B
TX_A
ISO3080
TGND
TGND
TGND
Schematic of bidirectional data port
The output driver capability of bidirectional data port can provide
a maximum of 60mA, and the minimum differential output swing
under 100 Ω load can be 2.3V.
A and B Signal Lines
Refer to sections Sensor Data Input Ports (previous page) and Bidi-
rectional Data Ports above.