Dear All,

I have a question regarding Modbus TCP/IP.

I need my Master and Slave device to communicate using Modbus TCP/IP. I'm using a Master device with an option for Modbus-RTU. Both Master and Slave device are interfaced using RS-485. So, Pals my question is can I interface both Master and Slave device using Modbus TCP/IP??? and between my Master device has an option for Ethernet (which is not enabled yet) but slave device hasn't got the option for Ethernet. should i use a gateway or a converter between these two devices to communicate??? or is there any other option.

Your help will be appreciated.
Thanks in advance
Anny

 

Are you having problems on the serial connection, hence you want to go ethernet?

You could use a Modbus serial-ethernet gateway on the slave end & use the ethernet option on the master. If there is the ethernet option it most probably is Modbus-TCP rather than Modbus RTU over TCP.

Hope this helps.

 

Look for a product called something like

- Modbus serial-ethernet gateway
- Modbus serial server
- serial to ethernet device server

from vendors like
- HMS Anybus
- Digi
- Lantronix
or a dozen others

Be sure to pay extra for the Modbus model/version.

 

Dear Anny,

If the slave devices do not support Modbus TCP then you will have to interface them using Modbus RTU. If they do not support Modbus TCP even a gateway might not work. I would like to learn a little more to confirm this. Feel free to write to me if we can discuss this.

Regards,
Jaimin
[email protected]

 

I'm not sure that a serial to Ethernet device server would work (except perhaps in the unusual scenario of Modbus RTU over TCP, which is far less common than actual Modbus/TCP). But a gateway should work fine. As indicated, many manufacturers do make such gateways: our is called the ETH-1000 and supports both Modbus/TCP client and server and Modbus RTU master and slave, so it should be no problem using such a device to do any sort of Modbus/TCP to RTU conversion required.

http://iccdesigns.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=ICC&Product_Code=eth1000

Regards,
Darrin Hansen

 

Thanks Balaji for your suggestion...
There is no issues regarding serial connection, I just need to use Ethernet option and check, as there is an option provided in my Master.

Thanks Again,
Anny

 

Thanks for your suggestion David

Anny

 

If you use a Modbus Serial-ethernet gateway, the modbus RTU slave device need not support Modbus-TCP. Our TSXETG100 is an inexpensive gateway which will serve Anny's purpose very well.

 

Anny,

Comtrol makes a Modbus gateway that does not only physical (Serial <--> Ethernet) conversion but also inter-converts between Modbus types. They support Modbus TCP, MB RTU Serial, MB ASCII Serial, MB RTU over TCP/IP, and MB ASCII over TCP/IP. You can have over 100 Masters of mixed types communicating to over 100 slaves of mixed types, simultaneously- the firmware behaves like a "Router" of Modbus messages. Check it out at:
http://www.comtrol.com/pub/en/Modbus-Router-Application

I have personally configured countless systems just like yours with this gateway.

RexTex

 

Dear All,
Thank you very much for all your suggestion and guidance.

Let me rewrite the question more precisely.

I have a Master device with an option for both Modbus-RTU and Modbus-Tcp/ip (not enabled yet). As I have been provided with Modbus-Tcp/ip option I need to utilize the same. Slave device has been enabled with Modbus-RTU mode alone. Presently my Master and Slave device both are communicating with Modbus-RTU mode. Now, I need my Master and Slave device both to communicate with Modbus-Tcp/ip mode. So from all your suggestions I got to know that I require a Serial-Ethernet Gateway.
I'm planning to design my own Gateway circuit, so can you all guide me regarding this.

All your help will be appreciated.
Thanks in advance,
Anny

 

Hi Anny,

You can use one of our new TGW-732.
http://www.icpdas-usa.com/products.php?PID=3761

between the RS-485 connecting your devices and the ethernet connection.