DeviceNet vs Ethernet


Thread Starter



I am replacing an MCC that is presently wired with DeviceNet. The new MCC manufacturer has the option, and recommends, using Ethernet.
If I stay with DeviceNet only the individual points will need to be reprogrammed in the DCS (deltaV). No additional hardware or cables will be needed.

If I go with Ethernet a new module (Monico) in the dcs will be needed for each MCC. Ethernet cable will be needed, and extensive reprogramming of the deltaV required.

So far it is a no brainer, from a cost perspective, that I just stay with devicenet.

So now the questions. Is devicenet on the way out and being replaced by Ethernet? I am trying to avoid ending up in a position where the devicenet becomes obsolete and we are forced to make changes down the road.

We are not interested in the additional information that can be monitored with Ethernet and since we need to go through the monico card most of that information would not be available unless points were specifically added to monitor them. Which can be done in device net as well.

Thank you for the feedback.
DeviceNet is not going away any time soon, but make no mistake, it <i>will</i> eventually go away as more and more people adopt Ethernet for new installations because of the other benefits it provides and comparative ease of use for new users. As my boss likes to say, "The network wars are over. Ethernet won, but the rest of them are in the jungle thinking the war is raging..." So even though you don't need those other features, the prudent move might be to convert new projects to Ethernet.

But that has to be weighed against possibly having to support two networks until all of your old D-Net equipment needs to be replaced. For many people, that means for the rest of their working life, so that can be a PITA. You already know D-Net and accept its shortcomings and limitations, plus Ethernet isn't offering you anything you need (at least not yet). But you said you ARE replacing a D-Net MCC, so is this the only one? If so, that may be an issue too.

If it were me, and I had other D-Net equipment to keep on the network, I would stay with the devil I know. But I'm outa here in 5-7 years tops, so I can afford to take a short term view.
Well, rather than "Ethernet", it SHOULD hinge on what protocol would be running over it. Ethernet/IP (CIP/ODVA)? Profinet? Some kind of proprietary thing that just happens to use Ethernet as a medium?

BUT.....since IMO DeviceNet is at its heart the work of the Devil, then no matter what the answer to the first question is, (except possibly some kind of obscure proprietary thing that has no degree of vendor independence), the answer would almost certainly still be to go with Ethernet.

Bob Peterson

I think DeviceNet is on its way out. It will be around for a long time just because of the installed base, but Ethernet is the longer term answer.

Do you want to add a bunch of brand new but already semi-obsolete parts to your plant? If so, use DeviceNet.

Do you want to not have to retrain your techs to use Ethernet? If so use DeviceNet.

Is the need to stock different spare parts an issue, then use DeviceNet and you won't need any new spares.

Are you nervous that 10 or 15 years down the road you will find that what you have is no longer well supported, and what support and parts you can get are very pricey, then select Ethernet.

IMO, DeviceNet is on the cusp of going away, and being taken over by better network choices. If you are going to retire before that happens, it won't make any real difference to you, since the fallout will happen after you are gone.