Accessing Siemens S5 PLC via Modem

[douglail]

i could use some help with this one.

I've been round and round with siemens AND modem manufacturer.

i'm trying to connect to an S5 115 PLC remotely via modem.
according to siemens documentation, you need a pair of modems that support 11 bit mode. they suggested Multitech ZDX modems.
i bought 2 of them.

they gave me a doc that is supposed to tell me how to do it with the multitech modems, but it doesn't work.

i get PLC timeouts when trying to go online.

i've been through their instructions step by step numerous times over the past two months, changing init strings, etc. all to no avail.

has anyone done this? can you help me figure out what is wrong?
i need the modem connection to be transparent, 11bit.

i've got a current loop adapter in line between the modem and the PLC, and i can go online fine when connected directly to it.

somewhere along the modem transmittion it's stripping control characters or reverting out of 11bit mode. but i can't track it down.

at the moment i'm sniffing the RS232 traffic coming out of the PC directly, and comparing it to a capture that was taken from the rs232 port coming out of the remote modem.

i can tell it's different already. but i can't tell how, yet.

 

[curlyandshemp]

Deja Vu

I recall this sort of grief back in the early to mid 90s supporting S5 installs remotely. The number of 11 bit data frame 9600bps modems was then very limited. I don't know what the situation is now regrading these types of modems.

What we discovered the hard way, was that is was easier to leave a laptop with PcAnywhere with Step5 or RealVnc with a Windows freeware program such as Pg-2000 from www.process-informatik.de at the remote locale.

Ian

 

[Fritz_frederix]

Hello,

I did the same thing as mentioned above. We were connected via a H1 network with our PG. On the PG we had installed Carbon Copy software instead of pc anywhere. It worked fine. Never done a direct connection with modems on the PLC.

Rudi

 

[moggie]

I have connected to many S5 PLC's without problem using the Tele-Professional II modems from www.process-informatik.de

The modems carry out the TTY conversion and can even be used with the old msdos based Siemens programmers.
I also believe that Process-informatik now have software for "standard" PC (internal) modems.

The Tele-Profesional modems are easy to use and set up.