Is DeviceNet Still Relevant in 2010?
In case you missed it we’ve started not only a new year but a new decade. Think about all the changes since January, 2000.
I don’t think I had a cell phone ten years ago. I know I didn’t have an ipod. I had a cassette player in my car and this bulky set of tapes that used to get stuck in the cars cassette player. [At least I was beyond 8 Tracks – look it up on the internet if you don’t know what that is].
Ten years ago, DeviceNet was still relatively new. It was introduced about 1995. Installations were just starting to roll it out in the late 90s. That pig, ControlNet, was in. 5 Meg and determinism. That was hot.
People said Ethernet wouldn’t make it. Way too expensive. Can’t daisy chain Ethernet they said and we have to daisy chain everything. No one, including me, could see how the prices for Ethernet switches would just melt away. Thank the lord our company never entered the switch business. I don’t need a product with 30¢ margins.
And no one could imagine the entire switch being integrated into Silicon so inexpensively that it can be part of a sensor. We’ve reached the day of daisy chained Ethernet. Wow!
So, it’s a new decade. Is the old guy, DeviceNet, still relevant? I’d argue yes but I’d qualify that a bit as you will see.
DeviceNet is built on CAN and CAN is really, really cheap. There are millions of devices that use CAN and the price of the silicon is next to nothing. In fact, it comes preloaded in almost every microprocessor you can find. All you need to do is to add a transceiver for about 60 cents and you have the hardware for DeviceNet. You’ll still need a small DeviceNet source code stack but that’s available fairly inexpensively. You can get either DeviceNet Master Source code or DeviceNet Slave Source code.
One thing about middle age is that all the kinks have been worked out. DeviceNet is now well understood. There’s tons of information on how to architect a network, figure out your power supply requirements and interface it to a higher level system. It’s now cookie cutter for a lot of installations.
Some might argue that DeviceNet is slow. That’s true but slow is relative. Most discrete processes really don’t need more speed than DeviceNet offers. 100, 250 and 500K baud are adequate for a lot of applications.
The only thing not going for it is that it isn’t Ethernet. Customers just love Ethernet because it’s all around them. They feel like they can handle it just as well as DeviceNet. But the costs are still going to be higher for Ethernet. There are currently not a lot of devices that are daisy chained Ethernet so switches (though cheap) still have to be bought, wired and maintained.
Yes, it’s a new decade, but I think we’ll see a lot of our graying, middle aged friend, DeviceNet.