I can't get DSC data logging to work!

[unclebump]

Do you have Diadem from NI?? When I used DSC 7.0, I flattened arrays into a binary string and wrote that data into Citadel. Not as convenient because you have to decode the historical data before viewing. I was monitoring cycles of data as we were making parts, not monitoring a long term trend.

[Jeremy_B]

Hi Keith,

The Read Trace VI has a time interval input that lets you select a subset of your data to return. 

[unclebump]

You might not be able to use the DSC module with the waveform data type. I found this info on the NI website.

The ways in which you can configure shared variables varies depend on the data type. Specify the data type of a shared variable on the Variable page of the Shared Variable Properties dialog box. You can use features the LabVIEW DSC Module adds with shared variables of the following data types: Double—A continuous value representation of a connection to a real-world input/output point. This type of shared variable can vary continuously over a range of values within a signal range. Use a double shared variable when you want to express a continuous value, such as 0 to 100. Boolean—A two-state (ON/OFF) value representation of a connection to a real-world input/output point. This type of shared variable can have a value of either 1 (TRUE) or 0 (FALSE). Use a Boolean shared variable when you want to express a two-state (ON/OFF) value. U32 Bit Field—A multiple-bit value representation of a connection to a real-world input/output point. This type of shared variable can consist of up to 32 discrete values. Use a U32 bit field shared variable when you have a multiple-bit value in which each of the bits represents a flag or single value that is turned on or off. The maximum length of a U32 bit field shared variable is 32. LabVIEW stores a bit field as a number that you can see in the National Instruments Shared Variable Monitor, but the bit field is an array of bit values. String—A string shared variable is an ASCII or binary character representation of a connection to a real-world input/output point. Use a string shared variable when you have binary information or an ASCII value. When you configure a string shared variable, you must select whether to treat the data in the shared variable as text or binary information. For example, you can use a string shared variable to obtain values from a bar code reader or if you have data that does not fit into any other data type. You also can use a string shared variable for PLC control strings and PLC reporting strings. You cannot use scaling or add alarming other than bad status alarms with string shared variables. LabVIEW also includes many additional data types for shared variables. Support of DSC Module features, such as scaling and alarming, for the additional shared variable data types is limited. National Instruments recommends that you use one of the above shared variable data types if you want to use the data logging features included with the DSC Module.

[Jeremy_B]

The Citadel database natively supports the datatypes used in DSC, however, it can log any datatype that you can have for a shared variable.  If you use a datatype that the database does not natively support, it will store it as a variant, and it is up to the user to convert the variant data back to its original datatype.

Unclebump is correct in that the DSC module only supports a subset of datatypes, and has limited support for the rest.  To summarize, you can log anything, but you might have to convert it manually, and some of DSC's features will only work with its supported data types (such as alarms or scaling).