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ABC 040104
3-15
3.6.1
SETTING RS 232 BAUD RATE
When the power supply is in local mode, command entry status , press
MENU
key until LCD
displays
BAUD RATE =
. The top line of the LCD indicates the current RS 232 baud rate (default
= 19200). Use
and
keys to scroll through the available baud rate settings (19200, 9600,
4800 or 2400). Press
ENTER
to accept new setting (new baud rate is effective immediately), or
CLEAR
to exit without changing setting.
3.6.2
SERIAL INTERFACE
The serial interface behaves like the GPIB interface in that the command is parsed after receiv-
ing a control character of either a Line Feed or Carriage Return. The serial interface supports
six special control characters. The six special control characters are:
Escape (1B
H
)
Causes the input buffer to be cleared. This character is used to ensure
that the buffer is empty when the host powers on since it is possible
that the ABC was previously powered on and received some charac-
ters prior to the initialization of the host computer.
Backspace (08
H
)
Causes the last character in the input buffer to be removed from the
input buffer queue.
Carriage Return (0D
H
)
Causes the input buffer to be parsed by the ABC.
Line Feed (0A
H
)
Causes the input buffer to be parsed by the ABC.
> and <
The > character turns on the echo mode upon receipt of the character.
The < character turns off the echo mode. The message “echo off“ or
“echo on“ will be displayed to confirm this.
3.6.3
RS 232 IMPLEMENTATION
The following paragraphs are provided to help the user understand how the RS 232 serial inter-
face is implemented in the ABC. Since the RS 232 protocol does not use a parity bit, the echo
mode is the default method used to ensure reliable communication between the command orig-
inator (computer) and the ABC power supply, thus avoiding a more complex “handshake” proto-
col.
When the ABC is in the RS 232 echo mode it returns all data sent to the host controller. The
ABC provides two additional options that allow handshake communication: the Prompt method
and the XON XOFF method. In standard echo mode the controller must verify that each charac-
ter is echoed back by the ABC. As shown in Figure 3-2, there are times when the ABC does not
echo back the character from the controller, requiring that the controller resend the character.
By using the handshake options (prompt and XON XOFF) the host controller can ensure that
serial data interrupts occurring after parsing of the incoming message do not result in lost data.
Figure 3-2 illustrates the default echo mode, the prompt method and the XON XOFF method
described in the following paragraphs.
Summary of Contents for ABC 10-10DM
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Page 14: ...viii ABC 040104 FIGURE 1 1 ABC SERIES POWER SUPPLY...
Page 18: ...1 4 ABCOPR040104 FIGURE 1 1 ABC SERIES POWER SUPPLY MECHANICAL OUTLINE DRAWING...
Page 19: ...ABCOPR040104 1 5 FIGURE 1 2 ABC POWER SUPPLY AND RA 71 RACK ADAPTER OUTLINE DRAWING...
Page 20: ...1 6 ABCOPR040104 FIGURE 1 3 TWO ABC POWER SUPPLIES AND RA 72 RACK ADAPTER OUTLINE DRAWING...
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Page 96: ...FOLD HERE Please place stamp here KEPCO INC 131 38 SANFORD AVE FLUSHING NY 11352 USA CUT HERE...