The Modbus
Master Serial/TCP Converter enables serial devices communicating on RS232/485
using the Modbus Master protocol, such as Operator Interfaces, to be connected
to an Ethernet network.
The Modbus
Master Converter performs two functions. The first being a modbus converter from
RS232/485 to Ethernet, and the second being a Web Server for configuration and
diagnostic purposes.
The converter
communicates using the standard Modbus/TCP protocol. The converter supports 4
TCP sockets. This means that a Modbus Master can communicate with up to 4 TCP
slave devices.
Each Modbus
Master Serial/TCP Converter has a unique Ethernet IP address which must be
programmed into the PC or PLC. The IP address in the converter is configured via
the Web Server. Any standard Web browser such as Internet Explorer can be used
to access the web pages were configuration is carried out. The converters are
factory programmed with a default IP address of 169.254.111.111. This address
must be changed before the converter is added to an existing network.
The web page
address for viewing the setup parameters is http://169.254.111.111/index.htm
The web page address for configuring the converter is http://169.254.111.111/ip.htm
 | SPECIFICATIONS |
Power Supply: 10 - 26 Vdc @ 140 mA
Ethernet:
10BaseT - 10Mbits/s twisted pair
RS485:
2 Wire Multidrop twisted pair -
Internal Jumper
RS232:
3 Wire , TX,RX,GND
Baud
Rate:
2400, 4800, 9600 and 19200.
Data Bits:
5, 6, 7, 8 .
Parity:
none, even, odd.
Stop Bits:
1, 2.
Connector: 11
Pin Connector on rear of module.
RJ45 on front of module for 10Base-T Ethernet
Power must be applied to terminal
1 (+12/24VDC) and terminal 2 (0V). The power LED will illuminate and all LED's will
be off.
Next the
Ethernet connection is required, either through a network or directly to a PC.
The Ethernet interface uses a standard RJ45 connector.
If the PC is
equipped with an Ethernet card but not connected to a network, a local network
address should be used for communication between the Converter and the PC. The
Converter is shipped with a default IP address 169.254.111.111. This address is
in the address area reserved for local networks not connected to the Internet.
For direct connection between the PC and the converter, a crossover Ethernet
cable is required.
To setup your
PC to connect directly to the Converter, an IP address in the same range as the
Converter must be assigned to the PC. In Windows environments, this should be
done as follows:
·
Connect the PC and the Converter together using
a crossover cable
·
Open the Windows Control Panel
·
Select Network
·
Select TCP/IP -> the PC's Ethernet adaptor
from the Configuration tab as shown below
| Click
the properties button. A TCP/IP Properties box similar to the one below
should appear |
| Select
the IP Address tab |
| Choose
to Specify an IP address as shown in the figure |
| Insert
the IP address 169.254.111.112 and the corresponding subnet mask as shown |
| Save
your settings by pressing OK in both TCP/IP properties and Network
properties |
| Reboot
your PC |
If there is an Ethernet network
available, the Converter can be connected to any Ethernet connection or hub
belonging to the network. If the PC is connected to a network, there is a strong
possibility that the default IP address of the Converter is outside the range of
the network (the address doesn't belong to the IP subset of the network). If the
Ethernet network is connected to the Internet, this is certain. In this case a
new IP address for the Converter is required. Contact the local network
administrator to be assigned a free IP address for the Converter. The new IP
address is programmed into the Converter using a Web browser software such as
Internet explorer. In this case the Converter must first be connected directly
to a PC as described above.
In the remainder of this chapter,
the IP address 169.254.111.111 is used as an example. Exchange this IP address
with the IP address you have set up in all the occurrences.
To test the connection between the PC
and the Converter, a simple program called ping can be used. Ping
sends a number of messages to the specified IP address and displays the
response. The ping program can be run from the command line or from a DOS window
on the PC, as follows:
| Open the Windows Start Menu |
| Click
Run |
| In
the Open box, type: "ping 169.254.111.111" |
If the network connection is OK,
the program will respond with:
"Reply from 169.254.111.111" and information about the response time.
If there is a problem with the
network setup the program will respond:
"Destination host unreachable". There may be two solutions to
this problem:
| If
the PC is connected in a network, change the IP address to an address
accessible from the local network. |
| If
the Converter is connected directly to the PC(or through a hub), change the
PC's IP address to one in the same address range as the Converter. |
If there is a problem with the
Converter the program will respond:
"Request timed out", this means that the Converter can not
respond to messages. Check the power connection. Check that the Link LED is
illuminated when the cable is plugged into the RJ45 connector.
The Converter has two built in web
pages. The first being for checking the configuration and the second is for
altering the configuration. To view these Web pages, a Web browser such as
Internet Explorer or Netscape is needed.
To view the default Web page in
the Converter, start the Web browser and type "169.254.111.111" into
the address line of the browser window. The main page of the Converter will now
be displayed in the browser window.
To view the
default Web page in the Converter, start the Web browser and type
"169.254.111.111" into the address line of the browser window. The
main page of the Converter will now be displayed in the browser window.
If no Web page is displayed, go back to
testing the network connection to the Converter by using the ping command. If
the Converter replies to the ping messages, check the setup of the Web browser.
If the Converter is directly connected to the same network as the PC,
"direct connection to the network" or "bypass proxy server for
local addresses" should be selected in the Web browser configuration menu.
If the Converter is connected to the PC through a firewall, a proxy server
should be selected in the configuration menu. Contact the local network
administrator for information about the network configuration.
The Web page
address "169.254.111.111/ip.htm" is entered into the address line of
the browser window to access the configuration page. This page allows you to
change the IP address of the MOD-MUX TCP Module, enter the IP addresses of the
slave devices, the range of slave ID's, setup the baud rate of the MOD-MUX TCP
Module on the RS485 network, and enter a Module Description Name for
identification/maintenance purposes.
| IP
Address: The new IP
address can be entered into the web page as shown above. After this has been
done, you must click the Submit button to send the values to the MOD-MUX TCP
Module. The screen will now be updated and if successful will continue to
display the new IP address. The new IP address will only be effective after
the MOD-MUX TCP Module power has been switched off and on again. This
feature allows you to check that the correct IP address has been entered
before being activated. If the IP address has been entered incorrectly and
the power has not been switched off, it is possible to re-enter the correct
IP address. If the power has been switched off and back on again, the
MOD-MUX TCP Module will not communicate until you enter the new IP address
into the address line of the browser window.
|
| Baud Rate, Data Bits,
Parity, Stop Bits:
The configuration of the serial port can be configured by selecting the
parameters from the pull-down menu. Click on the Submit button to load these
values into the MOD-MUX TCP Module.
|
| Module
Name: This field
allows you to enter a module description name into the MOD-MUX TCP Module.
This is an identifier for diagnostic/maintenance purposes and is chosen to
best describe the MOD-MUX TCP Module in the system by name or number.
|
| Slave
IP Address Poll Block:
The converter can be configured for 4 poll blocks. Each poll block is
assigned an IP address. This is the IP address of the slave TCP device.
|
| Modbus
Node ID Range: Each
poll block can communicate with a range of slave modbus ID's. Poll block 1
has the low range, Poll block 2 has the next range and Poll block 4 has the
upper range. |
| 
