Agilent Technologies 66332A, 6634B, 6633B RS-232Flow Control, RS-232Programming Example, Baud Rate

Introduction to Programming - 2

Baud Rate

The front panel Address key lets you select one of the following baud rates, which is stored in non-volatile

memory:
300	600	1200	2400	4800	9600

RS-232 Flow Control

The RS-232 interface supports several flow control options that are selected using the front panel Address key. For each case, the dc source will send a maximum of five characters after holdoff is asserted by the controller. The dc source is capable of receiving as many as fifteen additional characters after it asserts holdoff.

XON-XOFF	A software handshake that uses the ASCII control code DC3 (decimal code
	19) to assert hold-off, and control code DC1 (decimal code 17) to release
	hold-off.
RTS-CTS	The dc source asserts its Request to Send (RTS) line to signal hold-off
	when its input buffer is almost full, and it interprets its Clear to Send (CTS)
	line as a hold-off signal from the controller.
DTR-DSR	The dc source asserts its Data Terminal Ready (DTR) line to signal hold-off
	when its input buffer is almost full, and it interprets its Data Set Ready
	(DSR) line as a hold-off signal from the controller.
NONE	There is no flow control.

Flow control options are stored in non-volatile memory.

RS-232 Programming Example

The following program illustrates how to program the power supply using RS-232 to set the output voltage and current and to readback the model number and output voltage. The program was written to run on any controller using Microsoft QBasic.

NOTE: The power supply must be configured for RS232 and the same baud rate and parity as the controller.

‘Program to write and read via RS232.

‘Configure the power supply for 9600 baud, even parity and RS232

‘Configure serial port for:”

‘9600 baud

‘7 bit data

‘2 stop bits

‘Ignore request to send

‘Ignore carrier detect

‘ Even parity ‘ Needed with Vectra basic, ignored with QBasic

‘Send line feed

‘Reserve 1000 character buffer for serial I/O

DECLARE FUNCTION gets$ ()

CLS			‘ Clears screen
LOCATE 1,	1		‘ Position curser at top left
‘ Configure Com Port
OPEN “com1:9600,e,7,2,rs,cd,pe,lf” FOR RANDOM AS #1 LEN = 1000
PRINT #1, “OUTPUT ON”		‘ Turn on output then set voltage and current
PRINT #1, “VOLT 6”			‘ Set voltage to 6 volts
PRINT #1, “CURR .5”			‘ Set current to 0.5 amps
PRINT #1, “*IDN?”			‘ Query the power supply identification string
PRINT gets$			‘ Go to gets$ Function and print data returned
PRINT #1, MEAS”VOLT?”; volt			‘ Query the power supply voltage
Volt = VAL (gets$)			‘ Convert gets$ string to a value
PRINT gets$			‘ Print the value of the voltage
END			‘ End of main program

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