Asycube - Asyril SA
Operating Manual
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Copyright Asyril S.A.
Description
v1.7
FO 32.03.118
Operating Manual
Asycube
- Asyril SA
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Asycube Serial Network
2.5.4.
This technical note provides summarized guidelines and procedures to install and start-up a
Asycube RS485 network to communicate at half-duplex.
RS485 gives you two main advantages over RS232: longer cable lengths and greater
immunity to noise. In comparison to RS232, RS485 uses lower voltage and differentials
signals. RS485 is based on balanced circuits that rely on twisted-pair wires. The same two
wires are used to transmit and receive; therefore, within RS485 networks, only one device
can transmit while all of the other
devices “listen” (receive mode)
The network topology is a multi-drop bus. In either configuration, devices are addressable (up
to 15 nodes) allowing each node to be communicate independently. Only one device can
drive the line at a time, which implies that the drivers must be set into a high-impedance
mode (tri-state) when not in use.
Use shielded twisted pair cables to network the devices. Do not cross positive and negative
signals. Reversing the polarity will not damage the device, but it will not communicate. Do not
forget the signal ground. The function of the signal ground wire is to tie the signal ground of
each device to the nodes to one common ground.
-
End Node:
The device attached at both physical ends of the network, containing
a network terminator
-
In-Line Node: All devices connected to the network that are not end nodes.
Figure 2.21: "In-Line Node" and "End Node"
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