Remote PLC HMI/OIT Access

I'd like to get some opinions on how one might be able to remotely access a PLC across the internet for monitoring and/or programming.

Currently, when I want to remotely access and modify, from my home, a program that I'm working on at the shop, I have an inexpensive solution but it may not be the most efficient.

My solution requires that I have absolute control over the router separating the WAN (wide area network, i.e. internet) from my LAN. When I had DSL installed at my shop, I requested that a bridge, rather than a router be installed at my facility. I then installed a router for my firewall protection. Now, I can control and assign access, port assignments and redirects without calling up my ISP and requesting the change.

Next, I found software that works very well for remote desktop access called UltraVNC. Easy to configure and is not a hobbled version like RealVNC. A service like GoToMyPC has a monthly fee, UltraVNC is free. The server computer (PC I want access to) runs UltraVNC as a service and the remote computer has the viewer software installed. I can do anything from my home that I can do when I'm at the office. This does require that the connection speed be somewhat fast, but nowadays this is not a big problem.

I'd like to connect via VPN, but I don't see how the PLC will react since it cannot be configured to accept VPN communications.

I currrently do a lot of programming with Mitsubishi, Idec and Allen-Bradley (new to this within the past two years, so I usually post a lot of questions as I run into new issues). The installations are, so far, not on a SCADA, so the connection at the remote location would have to be dedicated. The installation are getting to be farther away from the office, so I'd like the ability to monitor any problems and program in the solution if practical.

How do you do this?

... rab

The way we normally set up customers so we can remote support them is to have a PC on their network we can gain remote access to.

This can be achived several ways (VNC, Webex, Citrix, PC Anywhere or even just a plain XP Remote Desktop).

Once this is up it means you can program anything you can see or remote desktop again to any other computer on the same network.
The only requirement is a static IP so we can hit the box consitantly and a user log in with the correct permissions on the customers network.

SLC_Integrator said:

The way we normally set up customers so we can remote support them is to have a PC on their network we can gain remote access to.

This can be achived several ways (VNC, Webex, Citrix, PC Anywhere or even just a plain XP Remote Desktop).

Once this is up it means you can program anything you can see or remote desktop again to any other computer on the same network.
The only requirement is a static IP so we can hit the box consitantly and a user log in with the correct permissions on the customers network.

Click to expand...

Ok. This kinda validates what I am thinking of. Yeah, I didn't think to mention the static IP address. In fact it's probably best that the customer have more than one so the PC available for remote access can be assigned its own and will isolated from the rest of the network. The only downside, it seems to me, is that the remote PC must have the application software installed. If this is A-B stuff, it can get expensive. However, better than flying back and forth for a 15 minute fix.

RBergmann said:

Ok. This kinda validates what I am thinking of. Yeah, I didn't think to mention the static IP address. In fact it's probably best that the customer have more than one so the PC available for remote access can be assigned its own and will isolated from the rest of the network. The only downside, it seems to me, is that the remote PC must have the application software installed. If this is A-B stuff, it can get expensive. However, better than flying back and forth for a 15 minute fix.

Click to expand...

Another option is using a dial-up connection to an ethernet modem, or if a PC is at the remote location, running HMI or SCADA software, a dial-up remote networking connection can be made.

No software is required on the dial-in computer , other than modem, and RealVNC which is free.

It is not recommended for remote updates, but is adequate to troubleshoot problems remotely, and gets away from having to involve IT

RBergmann said:

Ok. This kinda validates what I am thinking of. Yeah, I didn't think to mention the static IP address. In fact it's probably best that the customer have more than one so the PC available for remote access can be assigned its own and will isolated from the rest of the network. The only downside, it seems to me, is that the remote PC must have the application software installed. If this is A-B stuff, it can get expensive. However, better than flying back and forth for a 15 minute fix.

Click to expand...

If you have the solution provider licenses it isnt a problem as long as you secure it for your use only.
Alot of our customers dont mind actually buying the software though as one problems-worth of travel expenses/extended downtime is more than the cost of the software.

SLC_Integrator said:

The only requirement is a static IP so we can hit the box consitantly and a user log in with the correct permissions on the customers network.

Click to expand...

You could set up a Dynamic DNS. Most routers support DDNS or you could run a client application on the PC. Then your customers wouldn't have to spend the extra money for a static IP.

You can set up free DDNS hosting at - http://www.dyndns.com/

Tark beat me to it! Dynamic DNS works magically well!

Tark said:

You could set up a Dynamic DNS. Most routers support DDNS or you could run a client application on the PC. Then your customers wouldn't have to spend the extra money for a static IP.

You can set up free DDNS hosting at - http://www.dyndns.com/

Click to expand...