Devicenet Help - Rockwell SLC 5/04

[Gmitran]

Machine has existing DN devices that are connected to SLC 5/04. All communication is working fine now. Supplier wants to remove some DN devices from the network. Do I need to modify PLC program in order to continue communicating with those devices that are left on network? I have no idea on DN setup/programming. Network was setup years ago before my time. Thanks!

 

[widelto]

You have to use RSNetworx in order to remove devices from your DN network.
I would prefer to modify the PLC program in order to erase all the rungs related to the devices that were removed.

 

[Gmitran]

So I must remove the devices no longer on machine via RSNetworx in order to keep communicating with those devices still on machine? I prefer to not do any communication modification if I don't have to.

I have no issue w/ modifying program to remove excess program that are related to the removed devices. I'm concern with communicating with those devices left.

 

[Ken Roach]

Welcome to the PLCTalk forum community !

The removal of a couple of slave I/O devices will have a negligible effect on performance; there will be a couple milliseconds of reconnection attempt traffic every few seconds. DeviceNet does not pause and retry before moving on to the next configured slave device like some protocols like Modbus do. Ordinary DeviceNet configurations have enough "interscan delay" time between polling cycles to easily accommodate that traffic.

If you want to minimize that effect on a super-tightly tuned network, or you don't want to be annoyed by the error messages on the 1747-SDN for the missing nodes, you could go online with RSNetworx for DeviceNet, upload the Scanlist, un-check the scanlist Active box for the entries for those devices (without deleting the device entries or mapping), then re-download the scanlist.

If you aren't familiar with the software, and don't have archives or descriptions, it's probably best to either hire in an integrator to do that change, or leave the scanner alone.

 

[Gmitran]

TY Ken.

Speed doesn’t really matter on this network. There just be couple DN nodes left (PB station and digital I/O). I will leave network As-Is and ignore the DN module error. I can go back to update network w/o removed devices down the road, I just need to re-start machine for now (other contractors are involve with this maint and don’t want to hold them up).

 

[widelto]

What KEN say is correct, there is a small time wasted and It´s used to look for missing devices.
Removing unused rungs or disabling them must be done for the sake of clarity.

 

[Gmitran]

Yes, Widelto… Logic programming update won’t be issue as can do this. Thanks!