User manual

18
4.1 RS232C INTERFACE
The 1657 AC power supply has a RS232 interface in the rear panel for remote
communication. The serial settings are shown below:
BAUD RATE
9600
DATA BITS
8 BITS
STOP BITS
1 BIT
PARITY
NO PARITY
HANDSHAKING
NO HANDSHAKING
The Data format is shown as:
ONE
START
BIT
8 DATA BITS
NO
PARITY
BIT
1
STOP
BIT
4.2 CONNECTION DETAILS
The RS232 interface is a 9 pin D-type male connector (DB-9) on the rear panel.
Users must use a Null modem or Cross over serial DB-9 cable in order to
communicate with the instrument. The instrument uses only 3 of the pins, and
their assignments are shown below:
PIN NUMBER
DESCRIPTION
PIN 2
Transmit Data (TXD)
PIN 3
Receive Data (RXD)
PIN 5
Ground (GND)
9 PIN D-Type MALE Connector.
NOTE: Since the RS232 communication does not use handshaking, the
DSR input of the controller should be tied to a signal that is always