Distributed IO

[PG Eng 0]

Hi all, looking into an in house project for next year. I havn't previously done any work with distributed and/or networked elements, so looking for your advice... The attached file shows an overview of the rooms and what IO/controllers there are. If budget allows room 1 will have a RsView32 SCADA running. This is for a CIP project so not a huge amount of traffic I would imagine nor does it require a very fast response time. I would like to gather some data from the three PLC's in room 2. So what would suit best here in terms of RIO, Devicenet, just-run-a-multicore-cable-option etc? Thanks, PG IO_layout.doc

[PLCMentor.com 60]

Device net is not what i would pick for my first distributed network. In fact I usually avoid it like the plague (that may not be fair to the plague). I'm not sure I understand how this is a distributed application. You have two rooms with a few prox sensors in each room. They are only 10m from the room 2 plc why not just wire them direct to that plc? The costs of all the networking cards and remote I/O and time would be more than just pulling some wire. I think I am missing something. Are you wanting to put the valve panels on a network? How about explaining the rooms a bit more. As for networks, the 5/03 doesn't give a lot of flexibility. Of all the networks you listed, I think I would use RIO over the others. It's fairly simple - old, but simple and reliable. Any network with a SLC is going to take some time to come up to speed. If you have a chance to move up to the Compact Logix here then networking is its strength. Much easier and much more flexible, but I understand if you have equipment on hand or Ebay is involved with procurement. Lets not even get into the expense of getting a new software package if you dont have 5000. I also need to show my ignorance about the Ec3-60. What't that?

[Wassim 0]

Hello, Sounds like you need OPC for this. Have you considered that? Let me know and we can discuss this further. Thanks, Wassim Daoud Global Solutions Architect MatrikonOPC

[PG Eng 0]

CLX is a no go as we have only this year managed to get RsLogix 500 standard edition, so I can't see 5000 being financially feasible. Econ EC3-60 is a budget PLC, similar in exterior looks and ladder commands to Mitsi's. £550 for a 60 point (36 in 24 out) PLC, a 3.7" 20 key HMI, and necessary leads. The PLC and HMI software is free. http://www.listo-ltd.com/ This years project was to replace two SLC 150's in the block formers and to upgrade a DTAM on the 3rd to a PV 300, so I tried out the Econ's as a replacement for the SLC 150's (So far so good 38,000 blocks done so far).

[PLCMentor.com 60]

I cant really comment on the EC-60's as I dont have any experience with them. I think you mentioned a modbus link - that should be fairly easy to bring into a SCADA. Another network that I have not used much is Profibus. In the few times I have used it, it worked great. Similar to RIO in that it has been around a long time and is solid if maybe not the newest thing on the market. I have used 3rd party cards that worked with the SLC. The nice thing about the profibus is that you can drop some point I/O and talk with certain devices that have profibus interfaces. I am not sure how far you can go with it, but you are going to have problems with 1000m with most options - not to mention cost (I think I do remember RIO being able to go around 3000m at the slowest speed). Now Im writing in circles... Either of those two busses will have learning curves with the SLC, but you should be able to drop some flex or point I/O in your rooms and network to them. For your next project you may want to check out the Banner wireless I/O. We have had good luck with it and it will go some long distances. Come to think of it, you might want to check that out for this project. They have IP67 modules that you can just install into the area with a few points. The remote blocks can talk back to a gateway which interfaces with your PLC and leaves you the capability to expand. Sorry to ramble, but I get the feeling you are looking for options.

[paulengr 44]

I would consider splitting the differences again due to the short distances and the types of sensors. Consider going halfway. Brad, IFM Efector, and several others make nice "distributed I/O" panels. These have IP67 or IP68 M12 connectors on them and a multiconductor "pigtail" that is several meters long. Then you can buy plug-in patch cords that connect directly to the M12-terminated style sensors. The patch panel does all the power distribution and has diagnostic LED's on it. So with a 4-port panel, you've got 6 wires in a relatively thin cord coming back to your PLC panel (power, common, plus 4 signals). An 8-port panel has just 4 more conductors.