Many times, the raw tag values available to the user through an OPC-DA Server are not enough to perform valuable alarming. For example, given a temperature tag, the user may want to create an alarm condition for the "average 5-minute temperature," yet no "average temperature" tag exists in the OPC Server. The first solution is to use a calculation engine like OPCcalc to create a new tag containing the calculation result. The result tag can then be monitored.
This solution is recommended for complex alarming conditions.The second solution is to use the new Operation feature in TopView. Operations give you the ability to manipulate the raw OPC-DA tag value before it is used in TopView for alarming and notification. The alarm conditions are then applied to the result of the operation instead of the current raw tag value. All operations are performed within TopView - no tags to create, and no scripting or programming required! Tag operations include bit-masking, average, minimum, maximum, standard deviation, rate-of-change and mathematical operations between multiple tags and more…Evaluation download available.