What I do to configure DSC to read and log 5000+ tags?

[bruno_costa]

Hi, I'm developing a application thats need read and log a large tag database at period of 1 second. My system have actually 1200 tags and when I try to increase the number of tags my system slowdown and not update at requested period anymore. I'm using NI OPC Servers to read data of 4 different PLC's. In the SVE I've created an IO Server to bind variables and all variables are located in a single process. All variables are logging alarms and data. The Log Deadband and Update Deadband are set to 0. My machine is a DELL Precision T5400 with Dual Intel Xeon Quad Core with 4GB of RAM and Windows XP Sp3 installed. Bruno Costa Automation Enginner

[bruno_costa]

I'm including the lvlib and the NI OPC configuration file.

[unclebump]

Are you talking directly to plcs? If so, you might be able to set them up in I/O scanner mode, and the opc server in mailbox mode. This way the plc does nothing but transmit the values to the opc server, and you don't need to poll for data with two way communications. Is the data grouped into contiguous areas or spread out all over memory. One read of 100 consecutive registers would be better than 10 reads of 10 registers from all over the place.

You could also look at a multihome setup on the ethernet card in the computer. This gives the nic card multiple ip addresses. Each plc can talk directly to a unique ip address. Are the devices 10Meg, 100Meg, or 1000Meg for ethernet connections? Serial ports, forget about it. Maybe with modbus plus ports or data highway.

[unclebump]

You need to setup multiple channels in your opc server config. See the help file for the controllogix driver, then look in the optimizing section. Then think about using tag arrays and grouping like bits into a single tag and then split it out with array indicators inside labview. Also multihome your ethernet card in the computer and each channel can be assigned to a unique ip address. Might need a dedicated ethernet port in the plc rack just for the opc server communication. Keep it off the network that an HMI or programming software would be using.