8 Digital Communications Interface

8.1 Overview

The communication feature allowsan external device, such as a computer, to
communicatewith the 1529 to obtain measurement data and control operating
conditions. Communication is accomplished by issuing commands to the 1529
through RS-232 or IEEE-488 communication ports.

8.2 Communications

The thermometer readoutis equipped with an RS-232 serial interface, and op-
tionallya GPIB port. The serial interface allows communications up to dis-
tancesof approximately50 feet. Theserial interface and GPIB port allow the
user to access thefunctions, p arameters,and settings discussed in Section 7,
MenuFunctions.

8.2.1 Serial Wiring

The serialcommunica-
tions cable attaches to the
thermometerr eadout
through theDB-9 connec-
tor atthe back of thein-
strument.Figure 49 shows
the pin-outof thisconnec-
tor and suggested cable
wiring.This type of cable
is typically referred to as a
“nullmodem” cable. To
eliminate noise, the serial
cable should be shielded
with lowr esistance be-
tween the connector
(DB9) and the shield.
The serialperiod, baud
rate, linefeed, and echo
are programmable. Refer
to Section 7.5.1.1, Serial
Port, for instructionson
accessing and setting
these parameters.
Allcommands sent to the
1529 through theserial in-
77
8 Digital Communications Interface
Overview
Figure49 Serial Cable Wiring