ethernet/controlloix advantages

hey guys, the company I work for has decided they want to update our PLC5 machines to Controllogix with ethernet communication so they can monitor all the machines at a central point.

I am failing to see the logic. Yes PLC5's are old, but the programs work, the machines work. Are there things the PLC5 can't do? Im sure. But nothing we are interested in.

What advantage does Ethernet communication have over DH+? Is it a reliable form of communication?
Yes I assume you can network all the machines together and see what each one is doing, but wouldn't you need RSLogix5000 to access the machines? In which case the managers looking to see if machines are running are not gonna know what they are looking at.

I have a hard time getting behind any project unless I see value in it.

You can have ethernet on plc 5 by various methods. No need to change processors.

To get any meaningful data it will need to be extracted from the plc and put into a usable form like a database that updates a production report,HMI,or scada system.

Being able to program from your office is a nice benefit

Ethernet is reliable, fast and much more flexible.

Just ask them why and what they plan on gaining? Do they plan on speeding machines up or adding additional machines?

Years ago we started working on a machine rebuild that nobody would talk about. It turns out that uncle sam makes things on a need to know only if you are in the know, or until production rolls off the machines.

Do you all plan on doing the conversions inhouse?

Have a read of this post currently about a page back and look at the link in post by geniusintraining.
That is a Control Logix Gateway that gets DH+ onto Ethernet and would allow for orderly transfer in the future from PLC5 to Control logix

http://www.plctalk.net/qanda/showthread.php?t=59052

hey guys, the company I work for has decided they want to update our PLC5 machines to Controllogix with ethernet communication so they can monitor all the machines at a central point.

At some of our plants, we monitor the machines using PI. Its a process monitoring software. Everything is on ethernet and Control/Compact Logix. We are monitoring the uptime of the machines. If there are any type of problems, they can send maintainence out there at once to see why the machine is having problems. On some machines we monitor flow rates and this gives us the ability to look at pump or filter problems. We have a full time department that just monitors machines at various plants and gathers reports.

Also another benefit is if they have a problem with a machine, I can logon from anywhere (home, hotel, another plant), go online and determine the problem.

You could possibly do this using DH+ but it would be extremely slow. With ethernet you can see everything real time.

Another reason is the bean counters may also be looking at tax breaks and such when upgrading equipment.

Im sorry I was a little vague. I am actually on vacation right now. But got word that they are wanting a big meeting with me when I get back about switching these machines to ethernet. And while yes, they can do it with PLC5's, they(managers) have determined that it is more cost effective to upgrade to Controllogix and get their ethernet connectivity that way.

By posting here, I am trying to familiarize myself with Ethernet/Controllogix so I can give them a somewhat educated opinion.

I do not see us gaining anything by upgrading to Controllogix. This would most likely be done inhouse. The machines run fine. We can make them faster if we want right now with the PLC5's but our bottleneck is the mechanical ability of the machine.

I agree a frontend would be necessary for a lay person to gain any kind of meaning from what the PLCs are saying.

A tax break might be a reason for doing so, and if so I think it would an exciting project to work on. Good experience.

I plan on finding out all the answers I need next week.
Thanks for everyones input.

here are a few questions you might want to consider:

(1) are all of the existing PLC-5 processors already connected to DH+ ? ...

(2) how many stations/nodes (total number of processors and any other devices) are already connected to the DH+ ? ...

(3) are they planning on replacing all of the existing PLC-5 I/O at the same time – or keeping the existing I/O and "bridging/patching" it to the new ControlLogix processors with something like 1756-DHRIO modules? ...

(4) are there any "time critical" (high-speed) I/O signals involved in your systems? ... for a specific example: something like analog signals used for "positioning" applications? ... note: in many situations, a signal linked through a ControlLogix 1756-DHRIO module as "Remote I/O" is not as fast as the same signal when it was originally set up as "Local I/O" in an original PLC-5 system ... in simplest terms, the 1756-DHRIO "link" might become a bottleneck that did not exist when the I/O modules were located in the same chassis with the original PLC-5 processor ...

(5) how many plant technicians are likely to need extra training in order to work with the new RSLogix5000 software? ... note that I'm not talking about people who will work with the software day-in-and-day-out and become familiar with its differences, but rather the plant's maintenance technicians who only fire up a laptop once or twice a year – usually when forced to do so by having a production line down ...

personally, based on what you've posted so far, if all of your PLC-5s are already communicating over DH+, then I'd consider just "bridging" the existing DH+ network onto Ethernet ... in many cases this just requires a small 4-slot ControlLogix chassis with a power supply, an Ethernet module, and a 1756-DHRIO module ... note that a ControlLogix processor isn't usually a part of this "bridging" picture ...

if the intent of this modification is (as you said) just "so they can monitor all the machines at a central point" then replacing all of the PLC-5 processors with ControlLogix – and the conversion of all of your existing programs to RSLogix5000 – just seems like overkill from where I sit ... then again, maybe there's more to the story than any of us know about right now ...

final words of advice: be wary of how any existing I/O is going to be linked to the new ControlLogix processors ... in some cases, a communications bottleneck there can cause troubles that might not have been foreseen ...