AB Data Concnetrator

[timmyh]

Hey everybody,

Just wanted to get some advice on the best way to set up a Allen-Bradley Data Concentrator. There are about 8 remotes sites most of which have 50-70 tags I would want to bring into the HMI. We are using the MDS entranet900 radios to communicate with the sites. The Data Concentrator will be a 1756-L61 processor and the remote sites will all be Compact Logix brick 1769-l23e. What is the best way to get all the data to the data concentrator? Should we just message back and forth, or can you set up a UDT as a PRODUCER/CONSUMER tag and pass all the info back and forth? How much traffic do PRODUCER/CONSUMER tags cause on a network. Can you message an UDT? All the radios will be on a seperate network in the Data Concentrators Chasis. Do we have to worry about traffic with this small of a network?
Any advice will be helpful. Thanks in advance

 

[The Plc Kid]

AFAIK a produce /consume setup consumes 1 connection per tag over ethernet. That can be a single dint tag or a array.

I don't know about any size limitations on the array with produce/ consume though maybe some more experienced users can help there.

 

[ianingram]

I don't know about any size limitations on the array with produce/ consume though maybe some more experienced users can help there.

500 (or actually 512) bytes is the limitation ( I believe)
So this would mean 125 DINTS in an array.

(BTW, I just done a course, so I hope that I listened at the right point....)

 

[rdrast]

Yes, as long as the UDT structure is the same in the source and destination, you can MSG them back and forth.

For simplicity, I'd just have the L6x concentrator do a polling MSG Read (CIP Data Table Read) with your data UDT's and be done with it.

There is a 500 byte limit for any produced/consumed tag, without extra logic to break down the block into managable sized packets.

 

[timmyh]

Thanks guys,

I will probally go the udt route since it seems that it will be the quickest and will be albe to keep everything organized. Thanks again for the information.

 

[Firejo]

I’d use messaging (and FreeWave radios for that matter). The issue with produce/consume is that if 4 or more packets in a short time frame (I don’t remember the exact amount of time but it’s short) are dropped the UDP connection will drop and reset which will take from 4 to 8 seconds. If you are using TCP/IP (messaging) dropped packets won’t have that effect. Any hoping radio runs a high risk of dropping packets or delaying them which will have the same results. If you group the data into concurrent integers (N10:0 thru N10:10 for example) they can be read with one message instruction per remote site.