|
When designing a modern control
and monitoring systems of aids to navigation, the modularity and openness
of the system are the most important features for many customers. This
means that any system could be changed by adding or taking away of equipment
units without changing the whole system. It allows also building up a system
gradually, step-by step in accordance with
the financial and technical
resources of a customer.
The modularity and openness
of EKTAs systems are achieved by designing the system as consisting of
standard hardware and software modules which can be combined in different
modifications for different systems. To connect the modules together at
the lights level, there is the local area RS-485 twisted pair network,
or A-BUS. To this network up to 23 nodes or equipment modules in
any combination can be connected.
Features
-
Sending messages to other
nodes and receiving messages from other nodes about current state of a
node (power supply voltage under the load and standby, current consumption,
statistics, logical state etc.)
-
Exchange messages with the remote
control and monitoring centre through communication controller
-
Issueing commands to other nodes:
- light ON/OFF status
- lamp ON/OFF status
- switch to next lamp status
- synchronization of flashing
- controller test
- start Diesel engine
- stop Diesel engine
- clock synchronization
- time synchronization
- reset
-
Exchanging information with
other nodes:
- read working statistics
- get identification information
- clear error status
- get device status
- write new flashing pattern
- get measurement results |
 |
Specifications
| Physical
standard of the network |
RS-485 |
Transmitter signal voltage
between
+DAT and -DAT
by sending logical
1
by sending
logical 0 |
+1.5
5V
- 1.5
5V |
Receiver
signal voltage between
+DAT and -DAT
by receiving
logical 1
by receiving logical
0 |
+0.2
+7V
-0.2
-7V |
| Input resistance of the
receiver |
>12kW |
| Total
load of the network |
>54kW |
| Communication media |
twisted pair or shielded
twisted pair, recommended type 24AWG (0.2mm²) with line impedance
100
300W |
| Length
of the line |
up to
1.2km, when the length exceeds 50m then using 120W
terminal resistors at both end is recommended |
| Number of network nodes |
up to 23 |
| Data
rate |
9600bps |
| Data format |
start bit, 8 data bits,
marker bit, 1 or more stop bits |
| Data
coding |
NRZ, asynchronous,
half-duplex |
| Addressing |
individual or group |
| Length
of message |
from 6
bytes up to 131 bytes max. |
| Message package format |
destination address, own
address, length of package, users data up to 126 bytes, checksum, marker |
Download
the A-Bus cataloge page in Adobe pdf format
If you need more information, including
the information on prices and availability of our products, please do not
hesitate to contact our marketing group.
|
