ENBt and EN2T fw compatability

[WazMeister 0]

Hi All, 

 

Did some sesrching and used Allen Bradley links, but unable to find a reasonable answer. 

 

Can some advise on following questions. 

A system with PLC interlocking ENBt fm ver 4 with in the field ENBt ver 4 being upgraded. 

The new PLC with EN2T ver 6 did not work with the field ENBt ver4 (comms issues).    So tried ENBt firmeare ver 6 and this worked with the field ENBT...

The EN2T ver 6 worked with ENBT ver 6.

 

So why does the Master PLC EN2T ver 6 not work with ENBt ver 4?

 

Hope this makes sense?!?! 

[pturmel 159]

The ENBT's design goes way back, with features in later designs (and other ENxT types) not present in the earlier ones.  That's it.

[Ken Roach 194]

Quote

> The new PLC with EN2T ver 6 did not work with the field ENBt ver4 (comms issues). 

I would need more details about the type of "interlocking" and the nature or symptoms of the communication failures to guess.

Most features that the 1756-ENBT version 4.x firmware supported are also supported by 1756-ENBT version 6 firmware.    Certainly ordinary MSG instruction and Produced/Consumed Tags would be supported.   I might expect some issues if one of the systems is ControlLogix Redundancy.

You can read up on the details in the Release Notes:

https://literature.rockwellautomation.com/idc/groups/literature/documents/rn/1756-rn591_-en-p.pdf

Sometimes I have found that when you configure two devices and make a configuration mistake, you can mis-attribute it to the firmware revision, not to the mistake or difference in the configuration.    Or there's really a bug !

Edited 2 Apr 2022 by Ken Roach

[BobLfoot 301]

Lets dive into this a bit deeper.

BEFORE UPGRADE --

Master PLC - 1756-L?? CPU version ?? with 1756-ENBT v4 firmware

Slave PLC - 1756-L?? CPU version ?? with 1756-ENBT v4 firmware

?? Produced / Consumed tags

?? Message Instructions

AFTER UPGRADE --

Master PLC - 1756-L?? CPU version ?? with 1756-EN2T v6 firmware

Slave PLC - 1756-L?? CPU version ?? with 1756-ENBT v4 firmware

?? Produced / Consumed tags

?? Message Instructions

Can you fill in the details and if practical post the before and after programs from the PLCs?

[Joe E. 259]

I'm looking forward to Bob's deeper dive, but I'm not surprised at your symptoms or the solution. I've seen intermittent communication issues after upgrading the FW of a PLC that was talking through an -ENBT that were resolved by also upgrading the -ENBT. It got to where we kept a spare -ENBT standing by with the latest FW that we could set the IP address and do a quick swap in a live machine whenever we made a major change, especially one that required changing the PLC FW or adding any sort of Ethernet I/O devices.