SERIAL COMMUNICATIONS
37
Figure 29.
Organization of Typical Serially Transmitted Character
Figure 30.
Serial Transmission of a Complete Value, Including “CNT” Label, Value, “CR” and “LF”
After the entire value has been transmitted, the
control sends two more characters. These are
called “Carriage Return” (CR) and “Line Feed”
(LF). A printer, host computer or other peripheral
uses these characters to identify when a transmis-
sion is complete. In the case of the printer, the
“CR” instructs it to return the printing carriage and
the “LF” tells it to advance the paper one line. The
“CR” and “LF” are transmitted after each value
the control sends.
By selecting the associated value for the Commu-
nications Type function (Function 91) the control
can transmit the counter value or any combination
