KEPCO KLP Series Developers Guide, Rev 3 - Manual (Page 97)

KLP-DEV 041213
8-3
BS deletes the last character entered, with the exception of CR or LF characters. Either the CR
or LF character acts as the line terminator, initiating parsing of the ASCII data sent to the KLP
Power Supply by the command originator. When the line is parsed, the KLP sends the line ter-
minator sequence CR LF to the command originator.
The ESC character is used for synchronization, causing the KLP Power Supply to reset its input
buffer and return a CR LF sequence.
FIGURE 8-1. RS 232 IMPLEMENTATION [STANDARD MODELS ONLY]
8.2.2.1 ECHO MODE [STANDARD MODELS ONLY]
Echo mode is the default method of ensuring data is transferred without errors. Each byte (char-
acter) is echoed back to the sender where it is verified as the same character that was just sent.
If the character is incorrect or missing, the sender sends the character again until the correct
character is verified as having been received.
All non-control characters are sent via the serial port of the command originator. The control
character BS is echoed as BS Space BS. Only the first control character is returned in response
to either a CR LF or LF CR character sequence (see Figure 8-1).
8.2.2.2 PROMPT METHOD [STANDARD MODELS ONLY]
The command originator sends a message line (command) to the KLP Power Supply and waits
until the prompt sequence CR LF > is received. The KLP sends the prompt sequence CR LF >
to the command originator indicating the power supply is ready to receive the next command so
that data will not be lost. The prompt method is similar to the echo method described above,
except that the command originator does not have to compare each character and repeat any
characters dropped. The operation of the KLP is identical for echo mode and prompt mode;
implementation of prompt mode is at the command originator.
8.2.2.3 XON XOFF METHOD [STANDARD MODELS ONLY]
The XON XOFF method allows the KLP Power Supply to control when the command originator
is allowed to send data. The command originator can only send data after the XON (transmis-
sion on) character (011
H
) has been received; the command originator stops sending data after
receiving the XOFF (transmission off) character (013
H
), and waits until the XON character is
received before sending additional data.
Control characters, either CR or LF, are returned as XOFF CR if echo mode is on, and as XOFF
if echo mode is off. XOFF stops data from the command originator and the KLP returns the nor-
mal sequence of CR LF (if echo mode is enabled).