I have a PC - PLC serial communications project and the programmer on the PLC side wants to use DF1 protocol and send unsolicited messages. I have not been able to find any simple/inexpensive driver for the PC side to handle this requirement. I only need to receive a message on the PC and then reply to it, but don't want to spend the humdreds of dollars required for RSLinx etc. Any suggestions?

You can download a free DF1 driver for .net (DLL.net) here: http://www.tomantron.com./

or take a look at this thread: http://forums.mrplc.com/index.php?showtopic=4529&hl=

Thanks Ken, but the documentation for that driver specifically states that it does not support unsolicited messages.

The only software product that I am aware of that does Unsolicited Messaging over DF1 is RSLinx. You might investigate Kepserver EX too.

The Single-Node version of RSLinx is only $300... how much time were you planning to spend on this ?

Ken, thanks. Finding pricing for RSLinx has been difficult for me. The only thing I could find was a price of $795. If I can get it for $300, that might work. Thanks.

What is your location. Maybe someone on the forum can put you in touch with your local representative

I have now gotten a local contact and also a price from my PLC guy who is a reseller. Of course, it isn't $300, but $420. Thanks.

My fault on the old price, Greg. Being an analyst, I don't update my price lists very often.

Is this a one-controller to one-PC application ? If there are no other devices that need to use the communications channel, why does your programmer intend to use unsolicited messaging ?

Dear Greg:
You might want to examine the Automated Solutions DF1 Active X driver. It does unsolicited messages and used to be last time I used it a year or so ago cheaper than RSLinx. Although at a list of $499 that does not beat your $420. But then again you know how list prices are and they may come down to be competitive. They also offer a free trial AB-DF1 version for download, which you will not get with RSlinx.

Have you looked at KEPware http://www.kepware.com/ . We use it for Level II communications. I don't know the price but our IT guys say it was cheeper than Linx.