Wireless Serial & Wireless LAN Discussion 1

[robertjo]

I would like to get your opinions, and spur discussion on the role of wireless communications in the industrial control and automation arena.
Do you currently utilize wireless communications in your control systems?
If so, what type (i.e. serial radios, WLAN, integrated serial radio and RTU)? *** No vendor specifics please ***
Where do you see the future of wireless telemetry going?

I will start.
Our company utilizes several different types of wireless communication in control applications. I installed several 900 Mhz spread spectrum serial data radios when they first came on the market several years ago. Since then, there has been much advancement in wireless communications, including the explosion of wireless networking AKA WLAN. We started utilizing 2.4 Ghz WLAN to interconnect field offices several years ago. It was much cheaper that dropping fiber into existing facilities. We chose a device that operated under a proprietary protocol and had over the air encryption. We recognized early on the security risks associated with open protocols such as 802.11b, and wanted to make sure we didn’t head down that path.
Our equipment vendor did an EOL on the WLAN device we currently use, so we are looking for a new vendor who can deliver an industrial rated, 2.4 Ghz radio, operating under a proprietary protocol. We still have some time before they stop support all together, so we aren’t in a crunch yet.
We see the potential for industrial WLAN to grow like 900 Mhz spread spectrum grew several years ago. The only obstacle we see comes from the manufacturers. There seems to be a propensity towards using the same 900 Mhz bands that are currently over utilized in many areas to operate relatively narrow band 900 Mhz WLAN. Although these systems work relatively well for lower bandwidth intensive applications, these devices will not be able to keep up as our bandwidth requirements continue to increase (i.e. LAN enabled control systems).

 

[rayatucdavis]

Good start. We are also contemplating wireless solutions. Security is our biggest issue although line of sight vs. transmission through and around tall buildings on campus is also problematical.
Check out

http://www.iwasummit.com/

for information on a "wireless summit"

 

[Wfacac]

Here's my two cents, We work primarily with SCADA for several customers who have licenced frequencies already. Now everyone is security concious and wants video from remote sites. The narrow band radios won't do video and a secondary system works for the bigger customers but how do I keep the smaller systems up to date without telling them "You know that system we sold you a couple of years ago......?" With remote command and control steeping up into reality from just a buzzword I agree with you Robertjo, the manufacturers are stagnating. Even with the rebanding that may take several years to do I don't see alot of room for the data some customers want to move. For now it's alot of hybred systems and trial and error. I like mesh systems and I'm looking for a local municipality to try it on. I think we're going to blaze our own trails on this one.
I know I'm going to be real outspoken at IWCE this year.

 

[OldPfart]

Omron already have Device Net radio systems in place. They rely on line of site though but it is a big step forward for Device Net I/O.

 

[plcintegrator]

I personally would use existing WiFi 802.11g standard. As far as security goes I would lean in the direction of vpn tunneling. Take this scenario for example.

You have a scada server and 10 view nodes and you want to use wireless to connect the machines. For this example lets imagine that only one access point is needed because the nodes are all within range.

First I would purchase a WiFi access point that supports VPN tunneling.

Next put wireless cards into all of the computers.

Setup the tunnel within the access point with AES encryption.

On all of the nodes run client software such as ssh sentinel or something similar.

Also encrypt your WiFi signal with 128 WEP Encryption.

Now, not only is your signal encrypted with WEP 128 (yes this can be hacked) but your data is encrypted as well (this cannot be hacked). No one will be able to hack the vpn unless givin the shared key.

That is how I would implement wireless.



For professional plc, hmi, scada, and electrical engineering visit PLC Automation, Inc. at

http://www.plcintegrator.com

 

[robertjo]

PLCINTEGRATOR,

The scenario you lay out above would work in an office computing environment, but I am not sure it would work for field automation, where my focus has been lately.

Many existing devices in the field (i.e. RTU's, PLC,s flow computers, etc.) mainly support serial communications of some sort, and would require a terminal server device for network accessibility. I haven't come across a terminal server that has tunneling capabilities. Do you have a source?
Many manufacturers now offer ethernet ports as an option to their existing devices, but from what I have seen they are "dumb ports" with no encryption capabilities built in. Here is where I see a proprietary protocol coming in to play.
True, utilizing 802.11X and installing a firewall between your access point and the network, you could protect your network. But in field automation, the end device is as important, if not more important to protect than the rest of the network. If Joe hacker gets into your network, he could do some disruption and maybe some damage if you don't have full time intrusion detection on line. But the same Joe hacker could do serious damage if he were able to gain access to a field automation device, such as a PLC that is controlling a jet fuel storage tank system.
Do you see where I am coming from?
Currently there are a few industrially rated ethernet radios available with proprietary protocols, but the bandwidth is limited to around 512K or so. We are utilizing the Motorola Canopy for wireless video and interlinking business networks between offices. It has the bandwidth required, and has a higher level of security over the standard 802.11X devices. I works well in these applications, but the radio and antenna are housed together in a plastic housing and is not rated for classified areas and is not all that rugged. Also, I do not like having my radio out in the open on a pole and inaccessible. If there were a need to replace the radio, it is much easier if it is in an enclosure near ground level.
All in all, I see a big potential for wireless ethernet communications in the field automation and industrial control arena, it's just the manufacturers are lagging behind in development of usable, secure platforms.

Just my thoughts though...

 

[plcintegrator]

roberto,

I was just giving an example of securing scada nodes across a wireless topology.

Here is another alternative. This is a technology called junglemux from GE.

It's a SONET based system that supports wireless. One example is a light rail systems that uses wireless to communicate with rail crossing intersections. When the train gets within a certain distance it turns on the lights and puts down the arms to keep cars from driving over the tracks.

Just another suggestion.

For professional plc, hmi, scada, and electrical engineering visit PLC Automation, Inc. at

http://www.plcintegrator.com