Remote access to plc

Is the PSTN enough to connect the PLC to a remote access? do i have to have an ADSL or HDSL on the phone line or a normal telephon line (without internet connection) is enough? should it be a fixed IP? what is the minimum internet connection speed?

Thank you for your help

Hi Aazar,

An analogue telephone is capable of connecting to your PLC (you don't state which PLC you are looking at using, but in principle it will work), but it depends what you are intending to do with the connection. We have one customer who will only allow PSTN into their site and we find it painfully slow when we are asked to make programme changes (we can be online 30-40 mins sometimes). Can you not use some form of GSM/GPRS/3G modem instead (i'm assuming you have no LAN available at the remote site?).

If you can give a little more info on what you want to achieve and what equipment you have or intend to use, i'm sure we can answer your question a little better.

Hope this helps.

Rob

Thanks Kidblue for your help.

Actually i only have PSTN on site and no internet service on the line, so i need to to have internet subscription on the PSTN to make the connection, but i don't really know the internet specification which i should have to make the system work properly. Should i have an ADSL or HDSL service on the PSTN? should i have a static IP? and what is the minimum internet speed required?

Thanks again for your help.

Hi Aazar,

You have a couple of options with your current setup. You could use a PSTN analogue modem and just use the standard telephone number for that line to connect (you still don't state what PLC or protocol you have available i.e. are you planning to use the controllers serial port or does it have ethernet etc.) - these details will help you ultimately choose the best solution for your application. You could check out the AB Rades range of modems from Rockwell - they do a device that will connect PSTN to ethernet for example, again, more info is needed really...

If you go down the ADSL (DSL) connection route you don't need static IP (although it makes some things easier) - there are several free DNS services that will help if you have dynamic IP. More infomation is needed on what you intend to achieve.


Hope this helps.

Rob

Hi Rob,

Serial connection is used no ethernet port. This is the first time i connect my PLC thru PSTN, is the connection done by simpling calling the number of the standard telephon connected to the PLC without the need of the internet?

Thanks again for your support.
Alain