In recent tests we have read over 18,000 values at 70 Hz rate over Ethernet from Modbus devices and stored all this data to disk using our real-time logger (read database). This is a total rate of storing data to disk of over 1.2M values per second. All data read was stored as it was arranged to be a worst-case test. The log files have an SQL interface. Who needs this rate - well certainly not everyone but for 1,000-2,000 values per second there will still be some computer cycles left for other tasks. In the interests of accuracy, the values were predominantly digital Peter Peter Clout Vista Control Systems, Inc. 176 Central Park Square Los Alamos, NM 87544-4031 (505) 662-2484 FAX (505) 662-3956 [email protected] http://www.vista-control.com

 

Others have suggested it but IndustrialSQL from Wonderware is the way to go. It has a fast storage with hooks that go back to the MS SQL server. You get good compression, can store lots of data, and have access to the data through standard SQL queries.

Kevin Totherow