Moxa Technologies MGate MB3000 Modbus, Руководство пользователя, Страница: 57 / 89

MGate MB3000 Modbus Gateway User Manual 57
On the other hand, if you have manually set the routing table already, and you would like to enable the
auto-routing mechanism for the newly added devices, click No to keep the existing routing table. The
gateway will remain the existing user-set routing table and automatically route the newly devices. Note that
if a newly added device cannot be polled by the Modbus master correctly, the slave ID of this newly added
device might be set in the existing user-set table. Users have to modify the existing user-set table.
Another scenario is when legacy Modbus devices cannot set slave ID arbitrarily. It has a fixed slave ID or a
short range of slave IDs. Then, the slave IDs of the Modbus devices connecting to different serial ports will
be in conflict. The virtual-to-real slave ID function can help you to connect the same slave ID devices to
different serial ports of a gateway.
Let’s assume there are two legacy Modbus devices (named Device A, and Device B) with the same slave ID
1. Device A is connected to serial port 1 and Device B is connected to serial port 2. On the Modbus Master
side, the Modbus request for Device A is recognized by slave ID 1 and the request for Device B is recognized
by slave ID 2. You have to set the offset for the duplicate slave ID.
Real Device ID Virtual ID (Device ID recognized by Modbus Master) Offset
Device A 1 1 0
Device B 1 2 -1
Original Setting
Select the first channel and click Modify . The Slave ID represents the Virtual ID recognized by the Modbus
master.
The routing table will show up as follows: