Serial Remotes With Two Serial Ports - GE MDS SD4A Technical Manual

In this example, the Host Computer is connected directly to the radio's
Ethernet port, and the RTUs at the Remote sites are connected to the
COM2
transceiver via the radio's serial data ports. The IP Payload fea-
ture, used at the Master, efficiently passes TCP payload over the air, and
COM1
eliminates the need for an external terminal server. ( may also be
used for payload data if properly configured via the menu system. See
next example.)
Invisible place holder
Ethernet Data Port Menu
MASTER RADIO
(TCP Client)
To Ethernet Port
HOST COMPUTER
MODBUS RTU
(TCP Server)
Protocol
REMOTE RADIO REMOTE RADIO
(One of several possible sites) (One of several possible sites)
To COM2
To COM2
Serial Port
Serial Port
MODBUS® SERIAL RTU MODBUS® SERIAL RTU
Figure 9. IP Polling of Serial Remotes

Serial Remotes with Two Serial Ports

In some cases, it is necessary to poll more than one RTU at a Remote
site. Figure 10 shows an example of such a system. Here, two RTUs are
connected to each Remote transceiver, both using the radio's serial
COM1 COM2
ports— and .
COM1
By default, the radio's port is configured for serial management
functions with a connected PC, but it may be configured for data service
using the menu system. This arrangement allows two telemetry net-
works to share a single radio system.
MDS 05-4846A01, Rev. F SD Series Technical Manual 15