MB52XX Modbus Gateway
User Manual
Configuration
and
Setup
4.6.2
Operation Mode
To set the
Operation Mode
of the serial device that is connected to the Modbus Gateway through a COM port, use
the pull
-
down menu to select among the following modes under
Modbus Setting
.
RTU Slave
:
The serial device is working as a Modbus Slave node
:
the serial device will wait, accept request
from, and response to its Modbus Master node
.
Data transfer is done in RTU format
.
RTU Master
:
The serial device is working as a Modbus Master node
:
the serial device will issue commands
to or query Modbus slave nodes
.
Data transfer is done in RTU format
.
ASCII Slave
:
The serial device is working as a Modbus Slave node
:
the serial device will wait, accept request
from, and response to its Modbus Master node
.
Data transfer is done in ASCII format
.
ASCII Master
:
The serial device is working as a Modbus Master node
:
the serial device will issue
commands to or query Modbus Slave nodes
.
Data transfer is done in ASCII format
.
4.6.3
Serial Settings
This section summarizes the options of serial communication parameters used between the serial device and the
Modbus Gateway device over the selected COM port
.
RS
-
232
/
RS
-
422
/
RS
-
485
(
2
-
wire
)
Software Selectable
Baud
-
rate
:
1200 bps ~ 921600 bps Software Selectable
Parity
:
None, Odd, Even, Mark, or Space
Data Bits
:
7 or 8
Stop Bits
:
1 or 2
Flow Control
:
None, Software Xon
/
Xoff, Hardware RTS
/
CTS
Receiver Resistor
:
On or Off
Apply to all Serial Ports
(
check box
):
The settings can be chosen to apply to all serial ports if needed by checking
the last checkbox on the options
.
After finish the
COM Settings
configuration, click the
Save Configuration
button to save all changes that have been
made
.
A
Save Successfully
message will show up as shown in
and after a short period of time the web
browser will be redirected back to
COM Settings
page
).
Figure 4.10 Save Successfully Message
4.6.4
VCOM Settings
These settings will generate a virtual Serial
(
VCOM
)
port within the Modbus Gateway device based on a TCP
network connection
.
VCOM is a
TCP connection
which is encoded in an Atop Technologies
’
exclusive private
protocol
.
MB52XX series Modbus Gateway can only run as a TCP server which will be waiting for a connection
request from a TCP client
(
a serial device
).
Figure 4.11 shows the page of VCOM Settings in which the VCOM number 1 is set as an RTU Slave
.
This means
that a device that is connected to this VCOM port on the Modbus Gateway will be a Modbus Slave node and
communicate with a Modbus Master node using Modbus
/
RTU protocol
.
It is an interface concept that allows
Modbus Slave devices to be connected via TCP connection by using VCOM from a PC
(
for example
).
If a VCOM
