Connecting Rockwell PLCs

[SicknoteX]

Hi all,

I have a simple question about connecting 2 Rockwell PLC's.

We currently have a 1769-L32E processor communicating with an old DCS system via ModbusTCP (Prosoft card).

We're replacing the old DCS system and replacing it with a new Controllogix 1756-L81 processor.

What I'd like to do is remove the Prosoft card and get the 2 processors talking to each other directly. We have done this before very easily with 2 identical Rockwell processors.

The old PLC is running firmware v17 and the new Controllogix firmware will be running v31.

Can these 2 processors connect to each other over Ethernet/IP by simply Adding a device to the Controllers 'IO Configuration'? Or do they need to be running the same firmware?

Thanks

 

[the_msp]

You should be able to do it with produced/consumed tags

http://www.plctalk.net/qanda/showpost.php?p=571260&postcount=2

 

[Ken Roach]

As a general matter, the Firmware revision of the controllers doesn't matter with Produced/Consumed Tags. I could literally put a v2 and a v32 controller in the same backplane and exchange Produced/Consumed Tags.

The trick is the network path.

The 1756-L81 can definitely Consume tags that are Produced by the 1769-L32E because it knows about the older platforms and you can put a 1769-L32E into the I/O tree of the Controller Organizer.

I'm 90% sure that the 1769-L32E will be able to Consume tags produced by the 1756-L81. When the v17 firmware was created, there were no controllers with integrated Ethernet ports, so you always had to put an Ethernet module and a Controller in a specific slot into the I/O tree.

The standard workaround is to treat the newer controller like a 1769-L35E in the I/O tree, even if it's actually a member of the modern 1756-L8x or even 5069 CompactLogix families.

I haven't seen a verified occurrence of this not working; I've had people say "it didn't work" but then when I insisted that they double-check the IP addresses they never followed up.

 

[JosephMont]

As a general matter, the Firmware revision of the controllers doesn't matter with Produced/Consumed Tags. I could literally put a v2 and a v32 controller in the same backplane and exchange Produced/Consumed Tags.

The trick is the network path.

The 1756-L81 can definitely Consume tags that are Produced by the 1769-L32E because it knows about the older platforms and you can put a 1769-L32E into the I/O tree of the Controller Organizer.

I'm 90% sure that the 1769-L32E will be able to Consume tags produced by the 1756-L81. When the v17 firmware was created, there were no controllers with integrated Ethernet ports, so you always had to put an Ethernet module and a Controller in a specific slot into the I/O tree.

The standard workaround is to treat the newer controller like a 1769-L35E in the I/O tree, even if it's actually a member of the modern 1756-L8x or even 5069 CompactLogix families.

I haven't seen a verified occurrence of this not working; I've had people say "it didn't work" but then when I insisted that they double-check the IP addresses they never followed up.

Good information. I thought I had to update firmware when working with a older L3x and an L85 because the L85 was not in the catalog for that firmware. I will try this next time as I hate upgrading firmware on older systems.

Thank you!