Upgrading AB SLC 5/03 system to Internet Connectivity


Thread Starter

Townsley, Bill

Hi all:
This is a similar question to the recent SLC 5/03 DH485 / NET AIC question.

I currently have a system with the following components: SLC 5/03, DH485, PanelView900C (DH485 option), and a couple of AIC's. I would like to
upgrade the system to allow me to connect to the PLC via the Internet (security is another issue). I plan to also add a 'proper' HMI to the
system as well, although I have not decided upon which brand yet. Ideally I would like to be able to connect to the system on a remote PC and run the HMI as if I was 'just another node on the control network.' This would include using a web viewer on the remote machine to view the HMI pages (do not need an extra HMI license then). Ideally this would even allow the ability to upload/download the PLC and Panelview program to the remote computer.

I currently use a dial-up connection via modems to remotely 're-program' the PLC etc. This works OK but the long distance charges can add up pretty
fast. I also currently just get a data dump of all the PLC data files and manipulate/display them offline using Excel. The system was setup to have the PLC log all of the 'data' into its local memory. This includes the alarm logs as well. Seems pretty archaic but it actually works very well (just max's out the PLC memory...). I plan to move all of the data logging and alarm logging to a proper HMI in the future.

Should I change the control net to another type?
Should I install an Ethernet highway and use the SLC 5/05?
What OS should I plan to use for the HMI?
The 'palm pilot' type of roaming HMI gizmo is also a possible option but that would be way down the road.
Cost is obviously a factor since we have a shoe-string budget here.

Any suggestions would be greatly appreciated.


Christopher Di Biase

You have a couple of options here. If the control system has only one processor, your best option is to drop in a SLC 5/05 (yes I know its
expensive but what can you do apart than yell at your salesman about it) The SLC 5/05 would still be able to communicate to your pannelview so you could make your upgrades incremental to ease the budget and design strains.

If you've a larger system with a DH-485 network you could do one of a few things.

1. use a control logix gateway with a 1785-KA5P, a 1756-ENET and a 1756-DH/RIO modules to act as the Ethernet to DH+ to DH-485 bridge. I don't know how much that costs, but it would do the trick for you. Also should you ever migrate the control system to something other than SLC 5/03's and DH485 you'd still have your Ethernet connect ability.

2. use a workstation with RSLinx Gateway and a KTX card to act as the go between from the Internet/Intranet and the control system. If you're going to put this thing on the Internet this would give you more control over the
security with a lower cost. An RSLinx gateway can be configured to only allow access to specified IP addresses which could help keep unwanted visitors out of the system.

3. use one SLC 5/05 as an Ethernet to DH-485 bridge. This is must slower than a control logix solution, however it would be much more cost
effective. One important note, that some devices can not be seen though a SLC 5/05 bridge. This includes KE modules, KF3 modules and SLC 500, 5/01
and 5/02 devices. Also the only devices that could browse across that bridge would be IP addresses specified in the SLC 5/05's routing
table. This give you a measure of built in security, but it can also be a hindrance.

I think #2 is your best option, but that's just my opinion.
Hope that helps!
Christopher Di Biase
[email protected]
I think the easiest solution would be to use a Prosoft Make "Web Server Module". This module lets any HTML client view the PLC on DF1 protocol of Allen Bradley. Since you are using SLC 5/03,
the DF1 port should be available.

Rest of your system can remain untouched! Details of the product can be available at www.prosoft-technology.com.

If you can get rid of the PV900 and replace it with a PC based HMI, I would. Not sure about your environmental conditions.

You then would need a connection from your SLC 5/03 to the HMI PC. This PC would also be your "web server". Most HMI software companies have this component. Consider Iconics, you would could have a DF1 connections straight to your COM port, or use a AB PC card and connect on DH485. Use a OPC Server and the Iconics HMI. You could then use the HMI PC as your local HMI, and if you wanted to access the HMI over a Intranet, you could, by using there webserver software and Microsofts IIS. Your HMI screens could then be served over the Intranet and viewed with Internet Explorer. I am not sure if Iconics can go through firewalls yet or not, but might be needed if you planned on accessing it via the Intrenet. You would then be setting up essentially a small website serving up your HMI screens. Iconics sells its HMI software based on number of clients using at the same time as well as tags. Most HMI's sell somewhat simular.

There are several "packaged" solutions out there that will work for what ya need without upgrading the SLC unless a faster updates are needed.

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