I have a MODBUS RTU(RS485) at one end and TCP/IP (RJ45) at another end and I want to connect via Fibre Optic. Can a media converter convert directly from the fibre optic to RJ45 or I need an ADAM 4572 to convert MODBUS RTU to TCP/IP. I'm really confused between the media and the protocol.

 

Are you saying you have an existing MB RTU network and would like to interface that network with an Ethernet network (ModbusTCP,EtherNet/IP)?

If so, then you'll need a way for those two protocols to communicate. The link below is to a device that does exactly that. This has an RJ45 (copper) Ethernet connection and a RS232/RS422/RS485 serial connection for the Modbus RTU network.

http://www.prolinxgateways.com/products/4201.html

Now you'll need to convert the copper signal to fiber. The links below are to devices that do just that.

http://www.sixnetio.com/htmlhelps/catalog/5ce65fc.htm
http://www.ethernetrail.com/ethernetselect.asp#mediaconverters

Hope this helps.

- CH

 

Either it is RS485 with fiber in the middle or TCP/IP with fiber in the middle. You can do Modbus over TCP/IP. A RJ45 connector does not mean it is TCP/IP, could RS-232, RS-422, RS-485, Allen Bradley DH or DF1, FSK radio modem port.

Just like a DB-9 pin connector does not mean it is RS-232 communications, heck it could be analog signals.

I would convert the RS485 to TCP/IP, drop in a fiber convertor at each end, after doing my due research into the problem. Media or method of transmission is less critical then knowing what protocol your using at both ends.

Just make sure both devices are talking Modbus protocol, make the two compatiable by using either RS-485 or TCP/IP ports and if you desire drop in fiber in between.

 

Hello,
Frankly i must say i must know the structure of your Modbus RTUs. In a project we have used five RTUs as a ring and fiber optic (Cu to FO) converter and modems between them. There are some Telebyte Converters for this job. It is a just media. protocol is some other thing. For example you can use Modbus RTU as a serial port communication device or in port1 as a Modbus port in any case you will retrive data from table of locaql RTU or remote RTU throu Scada programm's IO driver and address mechanism. In Motorla Modbus RS 485 case it confiured and uploaded into RTU for that port and you must also configure other RTUs then through Cu-FO converters and FO cable on or modems and FO to other RTUs and devices connected to that remote RTU can be queried easily the media will just transfer all data packages this way or that way.
You see it is a bit hard thing to tell here just write me an email then i can inform you in detail.

Regards,
ismail
[email protected]

 

Matt,

I realize RJ45 doesn't always mean TCP/IP. In this case it does (read originating post) and that's what I based my response on.

- CH