Cognex OPC server and SQL

[Transistor 3]

I'm trying to use Cognex's In-Sight OPC server and an OPC data logger (AggSoft's Advanced OPC Data Logger, in this case) to record the results of each inspection by the camera. Machine cycle is 5s so we're not short of time. I have the choice of saving the inspection results in a 'wide' table (all the readings for one inspection on one database row) or in a 'narrow' table (one name/value pair per row). Here are my concerns: 1. How can I be confident that all the tags are updated before I write to the database? Typically OPC doesn't update the timestamp if the tag value hasn't changed. 2. How could this be achieved in 'narrow' format? I'd need some other inspection marker to accompany each name/value pair. The only thing I can think of is to have the camera construct a CSV string with the data of interest and change this after each job. Then I could get the logger to log 'on-change' but I'd have to parse the data somewhere along the way. Anyone come across this problem before? Many thanks.

[Stuartjl 0]

Hi, this maybe of use. The way it is done at our company the camera sends out a data string results after each inspection. This tells us that the inspection took place, i know one machine had an OPC server activated but they decided against this due to timing issues in when the opc server updated. With data string we definately new that a test had taken place.

[Transistor 3]

Thanks Stuart. The TCP data output is already going back to the PLC. The OPC server seems to update all the tags at once so it doesn't seem to be a problem. If anyone is trying something similar (OPC to SQL) then have a look at AggSoft's Advanced OPCDataLogger, Advanced TCPDataLogger or Advanced SerialDataLogger . About €125 for a licence with ODBC plug-in. http://aggsoft.com.

[Stuartjl 0]

Had another look at the one at work, i believe it does up date Access database through Visual basic. If you dont mind me asking what opc are you using?? dcom, tcp/ip??

[Transistor 3]

Stuart, Cognex Insight software comes with free OPC server. I have this, the Aggsoft Advanced OPC data logger and SQL server all on the one PC so there is no messing with DCOM, etc.

[Stuartjl 0]

Cool, easy peasey then. We deal with network systems here as well.