Misc. ControlLogix Questions

[dash]

Version 16 Comment/Question:

OK, the first item is the new Unicast connection that is available for EtherNET/IP connections. I really thought that this was also going to be available for I/O connections in addition to producer/consumer connections. From playing with it this morning it appears this is only available for producer/consumer connections for V16 processors and up. Does anyone know if this will be supported for IO connections in the future?


The last item is a request for clarification:
[The question below came up due to a statement in the tech support document 30621 DH+/RIO Message Management in ControlLogix - Tips to optimize the 1756-DHRIO. When to use the 1757-ABRIO module]

On a 1771-ASB module is it true that it can only support ONE BTR/BTW at a time for the whole rack? In the PLC-5 projects I have done in the past I do not remember this being explicitly pointed out. The only item I remember doing is interlocking multiple BTR/BTW to a single module in a local or remote chassis since it could only handle one at a time. I do not remember this being an issue for the WHOLE remote chassis.

In the document listed above the question comes up on page 4, item one on the list. "A Remote I/O adapter module (1771-ASB) can service only 1 Block Transfer at a time. So, when working with a rack with multiple analog modules when possible try to set up the message manager to enable 1 BTX per rack or spread them over multiple racks per group. "

Thanks for any insight,

Darren

 

[Contr_Conn]

Ver 16 unicast is for produced/consumed tags over ENET only
Ver 16 does not support unicast I/O and I will not comment on future releases

 

[Operaghost]

As to the remote BTR/BTW issue. That is correct. RIO will limit you to one Block Transfer per scanlist entry for each RIO scan.

This is why it was always recommended to put as much of your analog as possible in the local chassis where this limit does not exist.

OG

 

[dash]

OG, thanks. It is amazing that no matter how long you work with a Mfg controls, something always manages to sneak under your radar.

Darren

 

[Gerry]

some semi-relevant trivia

Some of the limitation was in the way the PLC5 communicated to the ASB. Apparently the ASB can queue transfers but is restricted to sending one per scan. The 5/250 exploited this capability to speed up BTX operations. Several BTR's could be initiated on one ASB in one scan and the data blocks would be transferred in subsequent scans. Saving of n-1 scans over the PLC5 method.

Question: can the CLX / DHRIO combination exploit this capability?