Require to establish Modbus RTU link between process analyser and PLC. Is there any free software that will enable a laptop to emulate the Modbus Master (PLC).

 

look at win-tech site, have good modbus master and slave emulator, free with a 3 min runtime.

 

http://mbserver.w3.to/

 

Yes, try the KEPWare OPC Server: http://www.kepware.com You can run it for 2 hours before having to restart it.

 

MODSOFT

 

Hi Take a look at www.modbus.org. I've seen slaves but I don't recall seeing a master. We will be needing one for the Linux PLC if Modicon will let us use Modbus freely. Let us know what you find. Regards cww

 

Much appreciated Peter. Thank you.

 

Kalpak, sorry for my delayed reply. Your help was great and is very much appreciated. I am just now waiting to acquire an 485-232 convertor.

 

Thank you, Larry.

 

Hi, Many good modbus (master/slave simulators) available over the web. You can try! BR/Girish

 

Modbus is an open protocol, so you should be able to use it freely. The spec is out, it's open, and you can download the book on Modbus communications from Modicon's website. Part number PI-MBUS-000. If you can't find it, I can order you one printed.

CK

 

Thanks, but what we need is free as in free speech not as in free beer. I can individually use it if I agree to license terms before downloading it. That license doesn't cover using with LPLC. I have asked them to allow this and have a dialog going with their chief IP lawyer. I haven't heard anything lately but they did respond to my initial inquiry, saying that we could use it under that license. I sent back email explaining the situation and we are waiting to see what they say. Regards cww

 

Curt, go to WIN-TECH. Here you can download both slave and master emulators.

 

Thank You But, Windows drivers are not of much use for the Linux PLC project. I was hoping for Open Source code we could use directly or port. A dependance on OLE would entail far too much risk in any case. Regards cww