RSLogix5000 to PLC5 Block Transfer Write

I am replacing a PLC5 with a 1756-L73 and i am trying to reuse a 1771-DB Basic Module. I am leaving the PLC5 in the chassis setup as RIO adapter mode and using the 1756-DHRIO card to communicate to the Basic Module. I am having trouble trying to do a Block transfer write to the Basic Module.
Currently i have the PLC rack added to my contrologix tree and it is connected via RIO. The MSG every now and then shows an error "Map instance undefined, or Block Transfer timeout". Anyone have and ideas or maybe an example of a BTW from ControlLogix to PLC5 with RIO? Im guessing my path is not right, but it is currently just set to my RIO card in the 1756 chassis.

Make sure your message type selected in the Configuration Tab is Block Transfer Write.

I've attached a screen shot of one of my MSG connections. I had a DHRIO as well and that was the only thing in the path. Make sure your Module Address selections are correct.

Are you sending data from a DINT tag or INT tag? The PLC5 will be looking for an INT, so be sure this is correct.

If you're still having issues, please tell us how your RIO network & DHRIO is set up - spare no details.

I am definitely using INT files. I am sure of the rack address and group. If i use any other rack address or group it fails constantly instead of timeouts. I attached images of my configuration.

I am wondering if it is something with the adapter mode on the PLC5. I have never used it before and im not completely sure how it works as i gave it an address of 27 in the adapter config, but anything referenced in the PLC program still uses address 0. Is this the way it is supposed to work? Can i even do a BTW with the PLC in adapter mode?

Just to test it out the basic module i made a PLC5 BTW to make sure it would send to the Basic Module, and it worked fine.

Wait, wait. I think you have a basic misunderstanding of how a PLC-5 Adapter Mode works.

It doesn't just turn the PLC-5 into a 1771-ASB. You cannot block transfer directly to a module in the chassis.

It makes that channel of the PLC-5 into a standalone adapter emulator. The N-files you designate behave like the discrete I/O, and the other N-files you designate can be block transferred to.

But that PLC-5 is still going to have to run the block transfers to the 1771-DB, and re-package that data for collection by the ControlLogix. Yuck.

Is it too late to revisit the 1771-DB conversion to a modern platform ? I'd hate to get through the whole conversion and then just have the long-obsolete DB module go toes-up.

Thanks Ken. That's what I was needed to know. I definitely don't want to pursue this path with that information. At this point I was just investigating my options. Thought it might have been quick and easy to do it that way. I'll completely remove that chassis and card.

Group and Slot vs Group and Module?

scott.maddox said:

I am definitely using INT files. I am sure of the rack address and group. If i use any other rack address or group it fails constantly instead of timeouts. I attached images of my configuration.

I am wondering if it is something with the adapter mode on the PLC5. I have never used it before and im not completely sure how it works as i gave it an address of 27 in the adapter config, but anything referenced in the PLC program still uses address 0. Is this the way it is supposed to work? Can i even do a BTW with the PLC in adapter mode?

Just to test it out the basic module i made a PLC5 BTW to make sure it would send to the Basic Module, and it worked fine.

Click to expand...

Can you help me understand how to identify group vs slot? Converting PLC5 to CLX and in my PLC5 code instead of slot it asked for module, and they are all 0. In the PLC5 instructions manual it mentions "Slot number within the group". Seems like group is the slot and module is always 0. Thanks in advance!

This is a really old thread, but check out pdf page 8 of the PLC-5 addressing manual (I can't find it on AB's website, so it's attached). It explains the Rack/group/bit numbering for each address.

I've also found the Quick Reference helpful:
https://literature.rockwellautomation.com/idc/groups/literature/documents/qr/1785-qr001_-en-p.pdf

This really gets back to what is called the Addressing Mode. The addressing mode identifies how I/O groups are assigned within a chassis.

2-slot addressing assigns one I/O group to two physical chassis slots
1-slot addressing assigns one I/O group to each physical chassis slot
1/2-slot addressing assigns two I/O groups to each physical chassis slot

So just for simplicity, lets say you have a PLC-5 in the processor slot and you are using 2-slot addressing. The next slot after the CPU would be Rack 00 Group 0. The slot next to that would also be Rack 00 Group 0. Then the next slots would be R00G1, R00G1, R00G2, R00G2, etc... If the chassis where a 16-slot chassis then the very last slots would be R00G7. So you count over two slots at a time. You will sometimes hear this referred to as "slot pairs".

So the "Module" term was used to identify if a module were in the left or the right slot within that slot pair. The slot on the left in the pair is Module "0" and the slot on the right in the pair is Module "1"

When using 1-slot or 1/2-slot addressing, there is only one slot to worry about. When using these methods, the Module would always be "0".

This can get a lot messier so I tried to not go deeper than necessary into addressing modes and stick to just enough to answer your question.

OG