EGX 100 PoE and externally powered

[raul_azzo_com_a]

Hi, we had several EGX 100 that were at the begging powered externally. After this, the power over Ethernet feature was activated in the switch, meaning that it was powered now from the PoE and externally. This made the EGX 100 restart every minute approximately, and once we disable one of the supplies, everything came back to normal. Is this a common behavior for this device? Is there something I could do to prevent these restarts having both power supplies ON?

[Digital_Hastak]

I have seen similar case in one of the Powerlogic KBs which confirms that EGX is not designed to be powered with both 24VDC and POE at the same time. Sometime it may also cause other issues where EGX is on POE with multiple downstream devices, but the ridethrough may not be enough to support them and this resets the EGX momentarily.

This may apply in your case too, where EGX may be giving priority to POE first when both are connected and due to lack of enough ride through, it may be resetting the device, and then resuming the comms again.

Hope this is helpful.

Regards,

Hastak

[dborle]

Yes, I can confirm this statement (as we had the same problem on a site)

Regards

Daniel

[JamesJeanette]

So...the EGX can have power going with both the 24V and PoE connected; although only one is used via a switch in the box.  If power is lost from the PoE switch, there is no interruption in service; however if both are connected and 24V power is lost, there is a reboot of the power as the PoE takes over.  We recommend to only use one source for power.  Also..if you are using PoE for power, be sure the PoE switch or PoE injector + switch is plugged into a UPS.

I hope this helps.

James

[JamesAZZO]

James,

You are saying that this should be working, but apparently this is not resolved? I think it might be particularly related to CISCO hardware which tries to look for PoE features and might not be static? Have you heard of anything specific to CISCO hardware? That might be related to what you are saying above with the short interruption of service?

Thanks.

James

[JamesJeanette]

I've not heard about any specific issues with hardware like CISCO.  From the engineers I understand the short interruption in service happens only when the 24V is lost, and switching over to the PoE.

[JamesAZZO]

This is happening a lot now for us. When you have 24Vdc powering the EGX and then connected to a Cisco router with PoE, it restarts itself and then loses it's IP Addressing. Do you have any testing on this?

[JamesJeanette]

Let me check for you.

[JamesJeanette]

Good news..the team will set up testing for this in the next couple of days to see what we experience.  We'll keep you informed.

[JamesJeanette]

Hi James D.,

This is from our verification and validation team...

"I'm having trouble replicating this issue. My EGX isn't restarting or losing it's IP address when the PoE is attached (with the 24VDC already powering it). Can you get some more information on the PoE switch involved (model)?  Also, if you could find information on what 24VDC power supply they are using, that would be awesome!"

Can you provide some more detail?

James Jeanette

[sesa10844_bridg]

We ran into a very similar situation at at customer site.  The EGXs were intially powered by 24VDC and were connected to a standard switch.  The customer later chagned the switch to a PoE switch.  The EGXs went offline, and were unresponsive.  We were told by tech support that the EGXs cannot handle having both the 24VDC and PoE power on at the same time.  It only works when there is one or the other, not both.  may be able to provide more details.

[raul_azzo_com_a]

Hi James Jeanette,

We have seen this happening with the CISCO 2960 and 2960S. The model of the power supply was the STEP-PS/1AC/24DC/0.75 from Phoenix Contact (we have use widely this with no issues). Is it possible to have more information about how the test was made?

[ganesh_azzo_com · Accepted solution]

Hi All,

The EGX does seem to operating as expected since the design was not intended ( As far as I know)  to support both 24VDC and POE at the same time

What is happening is that when 24VDC is disconnected the relays switches to use POE. This did not seem to have any effect with a single device connected to the EGX , however with multiple devices on the daisy chain the ride through is not enough to support them and the EGX momentarily resets, then resumes communication .

It is not stated that both the 24VDC and POE can be used at the same time, the intended use is for external 24VDC supply or the POE to be used for control power.

The only solution would be to use a software which would retry long enough to regain communication in the event this happens . Testing software (Modscan) does seem to time-out and lose communication when this happens, so connection through Modscan must be res-established manually.

[Charles_Murison]

What we found at the customer site is that the EGX would not longer communicate after a period of time and we needed to replace with a new EGX. When connected directly to the device we could ping the IP address however when we tried to open the webpage the device would not respond. Packet traces found little to no communication from the EGX.

[JamesAZZO]

I presume this is only being addressed by upgrading to the new hardware Com'X200?

[LaurentCoene]

Yes James: the Com'X fixes this issue (I think you've seen that already, but for others):

[dborle]

I think, that this will be an expensive solution to use a Com'X only as a gateway (what EGX100 is intended to be used for)!

[LaurentCoene]

That's a real good point!

[GrahamSpencer]

We have seen the same issue at Duty Free Shop in Guam.  The EGX300 (Firmware 4.350) was installed with an external PULS 24V power supply.  Months later, the local IT group turned on PoE and data stopped coming to Energy Operation.  Found the EGX300 in a weird stage (no access to webpage, no response to a ping).  Apparently orange light flashing - not sure if that refers to power LED, which should be green when normal.  They unplugged the 24V PSU from the 120V receptacle and the EGX300 rebooted and everything has been fine since then.  Thanks to JamesJ for confirming this issue to me via Sametime, but maybe I should have looked in SEC first. 😉

Practical considerations:

Note that we don't have much control over the customer IT group's use of PoE - might only appear long after commissioning the EGX!

Check that the PoE has a UPS backup in place.

With the current way the EGX handles its power source, use PoE if it is there and only install an external 24V supply if no PoE exists.

Even if the network goes down occasionally, with backup, the PoE will keep the EGX300 collecting RS485 connected data which can be sent once the network is back up again.

[Guillaume_Evrard]

Hello,

We have experienced weird behavior of one EGX100 and EGX300 (PoE powered) on a Customer site.

These EGX are  connected to different lines of ~15 compact NSX circuit breakers over serial modus.

Devices are polled by a PME and by a COMX200. ( Every 30 min by COMX)

Twice we could not get any replies for all devices for micrologic assocciated measurements ( I, U ,etc) but breaker status, number of operation were still reported.

A FSR went on site and confirmed that the EGXs seem to be stucked (LED status) . For EGX300 he had to plug the 24VDC for the EGX to start and removed it afterwards, for EGX100 Ethernet port unplug/plug => problem solved.

Is there any side effects with incorrect PoE voltage (Undervoltage ?)

Does anyone see  reasons to have only readings from BSCM and not from micrologic