Two PoE computers should be powered by a TSW202. Both are fixed to the same DIN rail and therefore share a common ground. When the second computer is connected to the switch, the first one is immediately cut from power, and neither can be turned on any more.
This is not the case when the second computer is detached from the DIN rail while it is plugged in. If it is afterwards attached to the DIN rail (while running). Both computer continue to operate normally.
We checked the ground levels between devices, and the DIN rail versus ground. Both are without anomaly. Grounding the DIN rail leads to the same issue.
The computers are both Fitlet3 equipped with a FC3-POED FACET3 card.
Is this a known issue? Is there a way we can operate both computers on the DIN rail, or do we need to isolate them somehow?
I’ll have to escalate this matter to our R&D for a comment on this, as this is not something that is easily replicable. Could you confirm whether the TSW202 is the only switch you have, or do you have another one that you could test with to confirm whether this issue is not related to the device itself?
I have tested the same setup with a second TSW202, with the same symptoms.
We currently have no other PoE switch here to test whether another model has the same issue.
The R&D have responded firstly inquiring whether there’s a chance that your setup might’ve caused a so-called “Ground Loop”? An example can be found here: TSW202 Powering Options - Teltonika Networks Wiki
Does not grounding the PSU or the TSW202 resolve the issue? Are you using any shielded cables perchance? Make sure the shielding is only connected on one side (that is, shielding shouldn’t bridge TSW and PD.
the power supply is not grounded, a ground loop between TSW202 and its power supply does not exist (no connection between minus and the grounding of the switch).
We use non-shielded ethernet cables.
We tested using one switch per computer. This works unless the negative terminal of the PSUs are connected (not grounded though), then the issue occurs.
