SAS Companion for the Microsoft Windows Environment

Reading Data Using DataMyte Processing

The SAS System under Windows supports DataMyte data collection devices through three SAS functions and one CALL routine. These functions are the DMYTECHC, DMYTECWD, and CMYTERVC functions. The CALL routine is DMYTECKS. These functions and the CALL routine are described in SAS Functions under Windows and SAS CALL Routines under Windows.

A full discussion of DataMyte processing is beyond the scope of this book; this section covers only the main points. A DataMyte is a data collection device that you attach to your communications port. The DataMyte device is typically used to interface with precision instruments in industrial and factory applications.

You can send data to and request data from the DataMyte device. A chunk of data passed at one time is called a packet. Each packet can be up to 255 characters long and can consist of several components. Two of these components are used by the SAS functions that support DataMyte data collection:

character count (CC), which is the number of characters in the packet excluding the start-of-text, the character count itself, and the checksum.
checksum (CS), which is the exclusive OR (XOR) of all the characters in the packet, excluding the checksum itself.

The following additional components are mentioned in the discussion of the SAS functions that support DataMyte data collection:

start-of-text (STX) character, which is always CTRL-B ('02'x)
end-of-transmission (EOT) character, which is always CTRL-D ('04'x).

For more information of DataMyte processing, see your DataMyte documentation.

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