Network Drop Out on Cable insert

[njhod1001]

Hi,

I have 2 x 200 series Smart switches creating a network that is distributed out from them.

They are running from UPS power and are connected by a single run back to a PC.

Both switches connect to local 5 port switches that are on a different power supply source and PLCs that are then connected to these local 5 port switches.

It all seems to work fine.

The issue is when I plug an Ethernet cable into the second 200 smart switch some devices drop out. It is as if they loose the network for long enough to go into fault. The PLCs are looking for network connection to each other.

Everything is as default out of the box.

I am using shielded Cat 6 cables.

Is the network drop out due to different earth potentials in the power?

The PLC that causes the fault is powered locally via a UPS.

The 200 series Smart switches are powered via another UPS and the 5 port switches and PLCs are powered via a 3 phase supply.

If I do not plug anything into the 2nd switch it all works.

Just concerned that there may be an earth potential issue or other issue that could be creating instability.

Any help appreciated

Nigel

[johnd2310]

Hi,

Are these PLC devices dropping from the network or are they losing power? If they are losing network access, then you could have a network loop created when you connect the cables. Make sure all the switches support spanning tree and there are no loops in the network.

Thanks

John

[njhod1001]

Hi John,

The PLCs are dropping the network. Power is continuous.

If I plug an unconnected cable into the switch I will get the issue. If it is connected to something like a laptop I will get the issue.

All of the switches/PLCs are connected by a single cable from one of the 200 Series Smart switches. They are not connected to each other.

It only seemed to become an issue when I had to power the main PLC from a different power source to the PC and main switches.

Would it be necessary to electrically isolate the feed to the main PLC being powered separately?

I am pretty sure I am not creating a loop, hence my concern about earth potentials.

Nigel

[johnd2310]

Hi,

Sound like you need an electrician to look at the power supplying those devices.

Thanks

John