Measurement Computing DASYLab User Manual - Manual (Page 60)

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7
Configuring the Data Flow
DASYLab transports data in the worksheet in blocks from module to module.
DASYLab does not output a data block to the next module until the current
data block is completely filled with data. DASYLab distinguishes
measurement data, which are from the measurement devices and data sources
and which most modules output, spectral data which are the result of a fast
Fourier transform, and histogram data which contain the count results of a
classification. DASYLab outputs a time stamp, the sampling rate, and the
block size with every data block.
The size of the data blocks and the sampling rate determine the processing
speed, which in turn determines the data flow in the block diagram. The
Block size specifies how many values a data block contains. The Sampling
rate specifies how fast DASYLab generates data or requests the
measurement values from the board. The Response time in the block diagram
depends on the ratio between the block size and the sampling rate. Table 7-1
lists the response times for some block sizes and sampling rates.
The response time specifies the period of time in which DASYLab accesses
all modules in a worksheet. Depending on the size of the worksheet and the
computer power, DASYLab cannot undershoot a certain limit.
If, for example, the worksheet comprises 100 modules and the specified
block size to sampling rate ratio is
0.001 s , DASYLab must process 100
modules in 1 millisecond. This leaves each module 10 microseconds to
process its data. DASYLab aborts the process because the time is too short.
Table 7-1. Response Time
Block size
Sampling rate
(1/Second)
Response time
(Second)
1 1 1
1 1000 0,001
1000 1 1000