I have been building my own HMI's using Visual Basic and a DF1 ActiveX control to communicate to Allen-Bradley PLC's via direct link cable. I am looking into setting up a remote PLC with phone line access only. I know I need a modem on both ends but I need some help with setting up my Visual Basic application to dial the modem and then use my DF1 ActiveX driver to communicate through the modem to the remote modem. For now I am going to communicate with a Micrologix 1000.

 

Donny---

Look in the documentation for your DF1 ActiveX control to find out how it supports modems.

If it doesn't, consider purchasing RSLinx Single Node from your Rockwell distributor. 9355-WABSNENE, $395,
"http://www.software.rockwell.com/rslinx/rslinxsingle.cfm":http://www.software.rockwell.com/rslinx/rslinxsingle.cfm .

RSLinx SN runs as a DDE/OPC data server on your PC, and can handle modem functions, including a phone book for your various dial-up targets.

In any case, be advised that DF1 over a phone line works best if you force ONLY 9600 BAUD and NO COMPRESSION at both modems. It's up to you to figure out how to configure the modems for those settings, using the documentation from the modem manufacturers.

Hope this helps!

Larry Lawver
Rexel / Central Florida

 

Thanks Larry, I have used RSLinx DDE but I do not want the end users of my VB Applications to have to also purchase RSLinx. This is why I use the ActiveX Control. The Control has a property which specifies the com port to use. I was wondering if I establish a link using the MSComm control and then specify the modem com port as the com property on the DF1 control if I could then send and recieve my data as if I were sending through my computer's serial port directly cabled to a plc, which I am currently able to do. The ActiveX control also has properties to set the baud rate and some other DF1 protocol parameters. Thank
You.

 

To Donny Zimmerman,

Since your email did not appear in the message, kindly email to me directly for further discussion on the above subject.

Rgds
-pklee
[email protected]

 

Donny---

I don't think MSComm can handle dialing and configuring a modem. I think your ActiveX control does more than MSComm already. The piece you are missing is the dialer.

Try configuring a Dial-Up Connection under Windows Settings. I think I see a way you can get the modem to configure and dial before your ActiveX comes into play. Remember, you must use the modems at both ends with ONLY 9600 BAUD and NO COMPRESSION.

Hope this helps!

Larry Lawver
Rexel / Central Florida