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MULTINET4 MULTI-PORT SERIAL SERVER & MANAGED SWITCH – INSTRUCTION MANUAL
SYSTEM ADMINISTRATION
CHAPTER 4: SYSTEM ADMINISTRATION
4.5.3.5 Modbus: Remote Slaves
This screen enables you to configure the forwarding table used to map Modbus slave
device addresses to remote IP addresses.
Table 4–51: Modbus: Local Slaves
Field Name
Field Value
Port ID:
A unique identifier for the serial port to which the device is
connected.
Device Address:
Modbus/TCP unit identifier assigned to the device.
Valid range = 1-247
Protocol Variant:
Specify a serial transmission mode. Valid options are:
• RTU – Messages are binary encoded with CRC and begin
with a silent interval of 3.5 character times.
• ASCII – messages are ASCII encoded with LRC and begin
with a ':' character and end with a CRLF sequence.
Default value = RTU
Priority (DiffServ):
Each IP packet generated by this device will be assigned a
DiffServ Code Point (DSCP) based on the priority set by the user.
The priorities are:
• Default – Best Effort Service (DSCP 0). This is normal
queuing.
• Expedited – Expedited Forwarding (DSCP 0x2E)
(RFC2598). This will also result in data from this
port having a higher priority on WAN ports.
Response Timer
(msec):
The amount of time to wait for a response from this device
before giving up and sending back a Modbus exception
message.
Send Gateway
Exceptions:
Specify whether or not to send exception codes. Possible values
are:
• Yes – Send Modbus/TCP exception codes when an error
occurs (for example, timeout).
• No – Remain silent when an error occurs.
Delete:
Set the Delete checkbox in a row in the Existing Devices table
and click
Apply Settings
to delete that local slave.
