American Magnetics 420 Power Supply Programmer - Manual (Page 94)

76 Rev. 7
Remote Interface Reference
RS-232/422 Configuration
4.3 RS-232/422 Configuration
The Model 420 allows several parameters related to the RS-232/422
interface to be configured by the user. See the Comm Setup Submenu
description in paragraph 3.2.4 on page 49 for illustrations of the menus
provided for configuring the Model 420 serial interface.
The Comm Setup Submenu provides menus to configure the following (the
defaults are shown in bold):
‡ Baud Rate: 1200, 2400, 4800, 9600
‡ Parity and Data Bits: Even Parity/7 Data Bits, Odd Parity/7 Data
Bits, No Parity/8 Data Bits
‡ Number of Start Bits: 1 bit (fixed)
‡ Number of Stop Bits: 1 bit or 2 bits
‡ Flow Control: None or SW (XON/XOFF)
4.3.1 Serial Port Connector
An IBM-compatible computer’s serial port can be directly connected to the
Model 420 via a standard PC modem cable if the Model 420 is configured
for RS-232. Refer to your computer’s documentation to determine which
serial ports are available on your computer and the required connector
type. The cable to connect two DB25 connectors is wired directly, i.e. pin 1
to pin 1, pin 2 to pin 2, etc. If a DB9 connector is required at the computer
interface, the connector translation is provided in the Appendix.
The Model 420, when configured for RS-232, uses only three wires of the
rear-panel DB25 connector: pin 2 (receive), pin 3 (transmit), and pin 7
(common). The RS-232 (and RS-422) pinout is fully documented on
page 112 in the Appendix. The Model 420 is classified as a DCE (Data
Communication Equipment) device since it transmits data on pin 3 and
receives data on pin 2. The computer or terminal to which the Model 420 is
attached must do the opposite, i.e., transmit on pin 2 and receive on pin 3
(the requirements for a DTE, or Data Terminal Equipment device). If a
serial-to-parallel converter is used, it must be capable of receiving data on
pin 3 or the cable connected to the Model 420 must interchange the wires
between pins 2 and 3.
Optional RS-422 connector pinout is provided in Table A-7 on page 113.
4.3.2 Termination Characters
All commands and queries are transmitted and received as ASCII values
and are case insensitive. The Model 420 always transmits <CR><LF> (i.e.
a carriage return followed by a linefeed) at the end of an RS-232
transmission. The Model 420 can accept <CR>, <LF>, <CR><LF>, or