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Writing ASCII text files that have greater than 16 channels

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Writing ASCII text files that have greater than 16 channels

Nowadays data acquisition devices have many channels some offering 64 channels or more. Using these devices in DASYLab one quickly realizes that the modules only handle up to 16 channels. Fortunately most of the modules can be used in multiples for example, the Daq device will allow more than one Analog Input module on the worksheet. However, when it comes to writing an ASCII text file containing many channel, it is not possible to use several File Write modules to write one file. The solution to this is to use Multiplex modules as shown below.

This example uses the multiplex module in both the multiplex and demultiplex form. To demonstrate that the data is crunched down to two streams, it demultiplexes the data stream to display the data.  To make wiring the example easier, the Copy Inputs feature on the File Write is used so that inputs are passed untouched to the outputs. 

To handle extra data coming in on the two channels, the File Write module allows the program to describe the data. The following dialog is from the File Write and the indicated section is where the channels get described. There are three sections to fill out, the Type of Input Data must match the Multiplexing Mode which is either Block or Single. [For demanding worksheets use Block mode to avoid throughput error caused by high sample rates.] The Number of Channel tells the module the number of channels on each input and they do not have to be equal. Lastly, the Channel Names are necessary because the channel names will not carry through the Multiplex module. So, if names were defined under the Slider and Generator and the names were copied throughout the worksheet, the correct names would not show up in the file. Therefore use global strings to hold the channel names and the Channel Name section to name each channel. After defining the channel names and setting the appropriate string to channel property, close the dialog and execute Options->Copy Channel Names from the DASYLab menu. Attached to this Article is the example demonstrating how to write 24 channels to one file.

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Article ID: 50372

Last Modified:7/29/2013 10:33:45 AM

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