catfish

QUOTE (crelf @ Sep 27 2008, 03:06 PM) It was an interesting show. If you are into torrents, its available over http://www.mininova.org/search/?search=history+hacker' rel='nofollow' target="_blank">here. Catfish ...

Thanks Mark & Jim for the great presentations & discussions last night. It was nice meeting everyone. Thanks JKI for the burrito & NI for hosting. Catfish ... (Mike Chaplin)

Hi Khalid, DSC Memory tags were the only real way to test the DSC engine performance alone. Once a tag is connected to a PLC point via an OPC server, then the performance being tested is that of the DSC engine+ the OPC server+PLC. The DSC engine will be the fastest of these three components by far. We used DSC network tags, some pointing to OPC servers tags for real I/O points, & others were memory tags used as "network globals" for communicating status changes between PC nodes running the DSC runtime engines. I've used datasockets to communicate variables between PCs that were not running a DSC engine. Did that answer your questions? Catfish ...

Hello, My experiences are with LV-DSC 6.1 (& earlier) from a couple of years ago. We used Modicon and AB PLCs on different projects with 1200 - 2000 PLC IO points. Imo, 1000 IO points is a LOT for data sockets. If the OPC server is fast enough, the data socket server *might* keep up, but the CPU load would probably be pretty high. The 6.1 DSC engine was fast enough & quite efficient (for "memory tags"), but its the OPC server & the PLC(s) that may not be fast enough. Test EVERY OPC server available (PLC vendor's, PLC-interface card vendor's, NI's, & 3rd-party like Matrikon) to compare performance & stability. There were very DRAMATIC differences between OPC servers back then. Before OPC & DSC, we used <http://www.softwarewithrelish.com/> products for PLC communications. Very reliable software with the added bonus of PLC comm errors being directly reported to LV. OPC & DSC comm errors did NOT get reported to LV6.1. LV8 shared variables *might* be faster than the previous DSC+Logos for "network tags", but as I stated earlier, its the OPC side of the house that will probably be your bottleneck with PLC points. The new features of LV-DSC 8 sound GREAT! I hope to work with it later this year. Good luck with your project! Catfish ...