BobLfoot

1756-EN2T Anomalies

11 posts in this topic

I have a 1756-ENBT Card in a 7 slot rack.  Tried swapping it to a 1756-EN2T configured identically for ip/subnet/gateway and could not ping it from the very same programming terminal that had beena ble to ping the ENBT.  Tried a direct connect cable and could ping it.  

Suspected something in the switch, but IT say not.  

Today tried 1756-EN2T in an open slot with another IP address and it pings.

This leaves Cable, Switch Port or IP Address as potential issues.

Any thoughts?

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Subnet mask? Default router address?

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Is it a Stratix or other managed switch? They can be configured to have individual switch ports set up on separate subnets. Sounds like you're already on the right track because if it's definitely not the switch, I'd change the cable to a different port, and then maybe swap the cables. If you plugged it into a different slot and it worked, could there be a problem with the first slot?

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Other than the obvious of divide and conquer through the network, there may be an issue with the new Mac and the ip compared to what the switch has in its Mac table. Try the en2t in the same slot with a new IP. This would tell me there's a mac issue in the switch. 

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OK here is the blow by blow and more details:

DAY 1 - SETUP -- 1756-ENBT @ address A.B.C.15 subnet 255.255.252.0 gateway A.B.C.1  ; 1756-EN2T address A.B.C.15 subnet 255.255.252.0 gateway A.B.C.1 ; Laptop NIC @ address A.B.C.201 subnet 255.255.252.0 gateway A.B.C.1. ; SCADA PC @ W.X.Y.Z 

ENBT experiencing FCS errors at 1-4 per minute.  Replace ENBT with EN2T and all looks ok except for flashing net LED.  Scada PC can't see or ping EN2T.  Use point to point cable from laptop to EN2T and it pings fine.  SUSPECT ISSUE WITH SWITCH CONFIG.

DAY 2 - IT Tech on site , opens admin terminal of switch , no port filtering, no access lists , nothing we can explain.  did identify two other ports on same vlan.

DAY 3 - SETUP -- 1756-ENBT @ address A.B.C.15 subnet 255.255.252.0 gateway A.B.C.1  in slot 1 of 1756-A7 and connected to switch port 10 vlan 2232; 1756-EN2T address A.B.C.25 subnet 255.255.252.0 gateway A.B.C.1 in slot 6 of 1756-A7 and connected to switch port 20 vlan 2232; Laptop NIC @ address A.B.C.201 subnet 255.255.252.0 gateway A.B.C.1. 7 and connected to switch port 14 vlan 2232 ; SCADA PC @ W.X.Y.Z 

Laptop can ping both cards, SCADA PC can ping both cards, NET LED of EN2T still flashing though.

I need the EN2T to work at the .15 address in slot 1.  Would the logix program thinking it's a ENBT somehow explain the card going non- responsive to the network?

frankly , I am puzzled.

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Here's a dumb question; Did you delete the ENBT card from the Logix project, then discover/install the EN2T in its place? As you likely already know, Logix is very particular about the cards in the I/O configuration, and there are a couple of gotcha's in the setup. Among those, an ENBT is not an EN2T, and I'm pretty sure you can't do a straight swap without changing the I/O configuration. This is why I rarely set one up manually, and usually go online and use the Discover function.

In any case, I'd go online with the controller and look at the properties dialog box of the comm card. Make sure the controller owns it (the card must be owned by a controller or it will not work) and that it doesn't have any errors or faults. You could also try temporarily disabling the Electronic Keying to see if there's a firmware compatibility issue.

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@ElectronGuru courious how you would go from project file A with ENBT running in plc to project file B with EN2T?

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The easiest way would be to delete the ENBT offline, download that project, go online and discover/install the EN2T. If you can't interrupt the process to do a download, then you'll likely have to delete any profiles & networks on the I/O tree below the ENBT, then discover/install the EN2T. Check that it's owned by the controller with no faults or errors, and then add the profiles & networks back.  

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Thanks @ElectronGuru I was going online with the 1756-ENBT project opening the properties of the ENBT and clicking the change button and changing it to an EN2T.  Once that was done I was disconnecting from the PLC and "hot swapping" the ENBT with the EN2T.  Following that I would lose the ability to connect to the PLC or ping the card.  Guess Rockwell's change button doesn't function as one would think.

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BobL, I've made the same discovery a few years ago.  Simply trying to "change" a module type or copy and pasting anything in the IO Tree usually fails.  Rather, it required a new instance and then download.

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