DADiSP Worksheet Functions > Function Categories > Real Time > RTWRITE

 

RTWRITE

Purpose:

Writes real time data to a file.

Syntax:

RTWRITE(len, freq)

len

-

Optional. An integer, the number of samples. Defaults to 1000.

freq

-

Optional. A real, the frequency. Defaults to 8 Hz.

Returns:

Places new series in W1.

Example:

Start first DADiSP to simulate a real time data source:

 

rttinit("rtwrite")

 

Start second DADiSP to read real time data:

 

rttinit("rtread")

 

The series generated by the first DADiSP is read synchronously by the second DADiSP. The real time data appears in W1 of the second DADiSP.

 

rttinit("rtwrite(300, 2)")

 

Same as above, but the series contains 300 points with a frequency of 2 Hz.

Remarks:

The first DADiSP writes a binary series to the file named RTDATA.DAT. An ASCII value of 1.0 is also written to the text file GATE.TXT to indicate new data is available. New data is not written to RTDATA.DAT until an ASCII value of 0.0 is detected in GATE.TXT.

 

The second DADiSP polls GATE.TXT. If the value is 1.0, the file RTDATA.DAT is read and the result is placed in W1. A value of 0.0 is then written to GATE.TXT to indicate that the new data was read.

 

Both the RTREAD and RWRITE are performed in the background via RTTINIT.

See Also:

RTREAD

RTTINIT

RTTTERM