I know many PLCs can connect to PC using modem and I only know the inital connection is from the PC to the PLC through dial up. is any PLC can be programmed to dial a number to connect to the PC and then communication?

 

Absolutely!. Many PLCs can dial out. There are several options: Send an ASCII string to make the connection, close an output that the modem is monitoring to force it to dial, toggle the DTR line and so on. Check on the dial up modems at http://www.miille.com/modemds.htm to see several types of modems that can do this.

Jerry Miille
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Jerry Miille
Miille Applied Research Co., Inc.
1730 South Richey
Pasadena, Texas 77502

713-472-6272 (voice)
713-472-0318 (fax)

 

Yes. If a PLC has a serial port and a transmit command that can be directed to the serial port it can and has been done.

 

There are a couple of industrial modems I am aware of that will allow you to do what you are asking. SixNet (http://sixnetio.com) and a European modem from Westermo (http://www.westermo.co.uk/main.html).

Hope this helps,

Darren Ash

 

Dear Miille,

Can your modems be with a Hitachi PLC and dial out to a Host PC through lease line or phone line?

Calvin

 

Calvin

I believe that they can but I have no direct experienct with the Hitachi PLC. Our modems can dial out based on a contact closure. Please contact me off list at [email protected] or 713-472-6272 to discuss your application further.

Thanks,

Jerry Miille