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Two different types of getting measurement and I/O data are available, "static" and "sampling". Both can be used in parallel.

 

Static data acquisition is very easy to use and the perfect choice for many applications. It is always active. The typical use case are measurement applications, where the working piece is fixed ("static") during measurement.

The measurement and I/O data is updated continuously with an update rate of approximately 30 Hz. The data is neither synchronized nor transferred in realtime. The update rate is not guaranteed and can be longer due to data packet loss.

It is started automatically after connecting to a device. The NMX DLL then periodically request new data from the device. This data is copied into an internal buffer. It can be readout at any time.

Often the static measurement is also used to achieve an online-view of the current measurement values.

 

Sampling is used to gather synchronized real-time data from the device. The typical use case are dynamic measurement applications, where high speed and determinism are required, e.g. for getting measurement curves.

It can be limited in time or it can be endless. Once started, the measurement system (device) acquires the measurement and digital I/O data in realtime and stores it into the internal device buffer. From there it is transferred in packets to the NMX DLL without real-time requirements.

Before starting sampling, various parameters must be defined, like the measurements channels used, the digital in-/outputs used and the sample period. Depending on the amount of sampled data and the sample period, the sampling must be time limited or can be endless. Consult the user manual / data sheet of your measurement system to see the possibilities. Typically 1000 Samples/s are possible with a large number of measurement channels.

The NMX DLL supports two general types of sampling:

•Low-Level sampling offers the possibility to perform time-triggered measurements. It provides the highest flexibility.

•High-Level sampling provides a simplified interface for performing complex real-time measurement tasks, e.g. position-triggered sampling. Internally it always uses Low-Level sampling. Therefore it is always optional and the high-level routines could also be implemented into the application software directly.