We have Cimplicity Plant edition interfaced to Seimens S7-300 PLC through the siemens PCMCIA LINK and an OPC server called Merz.

THIS IS BLOODY SLOW.

If we take one tag only in Cimplicity (or Merz) we can get it to refresh 5 times a second. If we take 5 points the refresh drops to about just over a second. By the time we take our 136 points refresh of all the points is upto 7Sec. Making all the graphics very jumpy.

My opinion of Scada was that it should cope with hundreds of points, if not thousands, at reasonable refresh rates. 136 tags is not that many points.


Points I can tell you :

1) Data inside PLC is in multiple not contionous blocks
2) Not all points are required all the time 36 (about 4 times a second) are need all the time 100 are configuration needed only when they have to be changed.
3) We have tried running the pcmcia link at 6Mbs on profibus and at 187.5kbs on MPI with little or no difference. But, both are slightly quicker than the Serial Link!
4) Laptop runing cimplicity ins pentium II with 128MB RAM running Win 2K Sp2. With 2G Free on HDD.
5) PLC is running high speed maths on a 25mS timer using 15ms of Time.
6) PLC is Siemens S7-315 with out DP interface. I have access to a S7-315Dp for testing only.
7) I have been speaking to Siemens, Cimplicity(GE-Fanuc) and Merz about this problem but at this point They havn't resolved it.