Controllogix, rslinx and HMI OPC Client

[wilsonzhu]

Hi,

I have a question, when doing controllogix PLC programming, Do we need create special UDT(Continuous Block in memory) for HMI OPC Client to read/write through RSlinx OPC topic for improving communication efficiency? Thanks.

 

[fuzzy logic]

Basically yes:
collecting data contained in arrays or UDTs that can be optimized will use less ControlLogix processor CPU resources and memory.
UDT optimization works by having RSLinx Classic grab the entire UDT structure when any of the structure’s members are put on scan and the UDT optimization is enabled in RSLinx Classic.

For a more complete and detailed description about the RSLinx Optimization, I suggest to read the Application Guide you may find inside the RSLinx Installation disc, Online documentation,file named "CLxPerf.htm" (ControlLogix Data Collection with RSLinx Classic)

- fuzzy logic

 

[Paullys50]

As Fuzzy said, yes you do! Well, to be clear you can use arrays too. Also, you need to be very aware of how online PLC changes can affect RSLinx. There is a "best practices" guideline out there that tell you what can impact RSLinx comms while you perform online edits. If you aren't careful you can put RSLinx into a "slow poll" mode, which cripples your comms.

Also, be aware of the number of clients you have talking to a processor, the more clients, the more problems you will have especially if your comms are inefficient.

 

[daba]

As Fuzzy said, yes you do! Well, to be clear you can use arrays too. Also, you need to be very aware of how online PLC changes can affect RSLinx. There is a "best practices" guideline out there that tell you what can impact RSLinx comms while you perform online edits. If you aren't careful you can put RSLinx into a "slow poll" mode, which cripples your comms.

Also, be aware of the number of clients you have talking to a processor, the more clients, the more problems you will have especially if your comms are inefficient.

Multiple clients should be accessing PLC data using RSLinx Gateway, so that only one RSLinx is actually fetching data from the PLC - the other clients are getting that data from the Gateway.

 

[Paullys50]

Multiple clients should be accessing PLC data using RSLinx Gateway, so that only one RSLinx is actually fetching data from the PLC - the other clients are getting that data from the Gateway.

Exactly!!!