B&B Electronics Vlinx MESR9xx - Manual (Page 32)

4. Properties Vlinx MESR9xx Modbus Gateway
Page 28 Manual Documentation Number MESR9xx-4508m
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• RS-485 4-wire - Similar speed and distance specifications as RS-422 but allows
multi-drop and full duplex connections. Typically uses two shielded twisted pairs
and screw terminals but DB-9 connectors are also used on MESR9xx Modbus
gateways..
Select the appropriate serial interface mode for the type of connection between the
Modbus gateway's serial port and the device connected to it.
Note: Refer to the Appendix D for connector and pin-out details.
Modbus Gateway Name
Modbus Gateway Name is a unique name assigned to the Modbus gateway. It must be a
valid hostname as defined by RFC-952 and RFC-1123. The rules are:
• It must consist only of the characters "A" to "Z", "a" to "z", "0" to "9" or "-"
• It can start or end with a letter or a number, but it must not start or end with a "-".
• It must not consist of all numeric values.
Gateway Serial Port Number
The Gateway Serial Port Number of the currently selected port is shown in this field.
• MESR901-x Modbus Gateways feature one serial port.
• MESR902D-x and MESR902T-x Modbus Gateways feature two serial ports.
Subnet Mask
The Subnet Mask specifies the network mask the Modbus gateway uses when on a
subnetted network.
• For a Class A network (IP addresses 0.0.0.0 through 127.255.255.255) the default
subnet mask is 255.0.0.0.
• For a Class B network (IP addresses 128.0.0.0 through 191.255.255.255) the
default subnet mask is 255.255.0.0
• For a Class C network (IP addresses 192.0.0.0 through 233.255.255.255) the
default subnet mask is 255.255.255.0