DeviceNet node limits

Buck Bonzai · May 10, 2007

I'm new to DeviceNet and understand you can have 64 nodes on a network, leave 0 and 1 for scanners, 63 is for new unaddressed nodes but I was wondering if there is a general rule of thumb to how many nodes you can should have on a network? I've been hearing around 40.

widelto · May 10, 2007

The maximum numbers of nodes I have installed are 20, however i have not heard of practical limitations.
In other of my installations the scanner is number 63 so it is not true that the scanner has to be 0 or 1.

allscott · May 10, 2007

It's really 63 because you do not want to set any of your nodes to 64. When you install a new device that is not dip switch settable it will automatically show up on 64 until it is configured so you don't want something permanently on that node

DBLD99 · May 10, 2007

The limit also depends on what devices you have on the network you have all DSA's you could have 63 DSA's, but if you had a lot of Powerflex drives with all the Datalinks enabled you would fill up your scanner pretty quick.

Jimmie_Ohio · May 10, 2007

allscott said:
It's really 63 because you do not want to set any of your nodes to 64. When you install a new device that is not dip switch settable it will automatically show up on 64 until it is configured so you don't want something permanently on that node

Your description is close to being correct.

There are 64 nodes TOTAL, numbered 0 through 63. New devices generally default to node 63 so that is the one to wisely leave available. FYI, I think it's wise to make the scanner node 0 since you always need that... Other nodes may change and adjustments can be made to accommodate those changes.

mordred · May 10, 2007

here is some of Phils articles on devicenet and other configurations I've been placing them into one file for easy reference found it very useful that way

BobB · May 10, 2007

I do not know about other brands but I believe the Omron Device Net scanner is limited to 300 words so you have to be careful how many words are allocated to a module as well as the physical limit of 64. Expicit messaging to some devices on a network will release quite a lot of words but does slow down the communications somewhat.

DeviceNet node limits

Buck Bonzai

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widelto

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mordred

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