9 Digital Communication Interface
The dry-well calibrator is capable of communicating with and being controlled
by other equipment through the digital interface. Twotypes of digital interface
are available— the RS-232 serial interface and the IEEE-488 GPIB interface.
Witha digital interface the instrument may be connected to a computer or other
equipment. This allows the user to set the set-point temperature, monitor the
temperature, and access anyof the other controller functions, all using remote
communicationsequipment.
9.1 Serial Communications
The calibrator is installed with an RS-232 serial interface that allowsserial
digitalcommunications over fairly long distances. With the serial interface the
user may access anyof the functions, parameters and settings discussed in Sec-
tion 8 with the exception of the BAUDrate setting.
9.1.1 Wiring
The serialcommunications ca-
ble attaches to the calibrator
through theDB-9 connector at
the back of the instrument. Fig-
ure 9 showsthe pin-out of this
connector and suggestedcable
wiring.To eliminate noise, the
serialcable should be shielded
with lowresistan ce between the
connector (DB9) andthe shield.
9.1.2 Setup
Before operation the serial in-
terfacemust first be set up by
programming the BAUDrate
and other configurationparame-
ters. These parameters are pro-
grammed within the serial
interface menu. The serial in-
terfaceparameters menu is out-
lined in Figure 6.
Toenter the serial parameter
programming mode firstpress
9105/9107 43
9Digital Communication Interface
RS-232 Cable Wiring for
IBM PC and Compatibles
1NC
2RxD
3TxD
4NC
5GND
6NC
7RTS
8CTS
9NC
2TxD
3RxD
4RTS
5CTS
6DSR
7GND
8DCD
20DTR
Instrument
Connector
(DB9-Pin)
Computer(DTE)
Connector
(DB25-Pin)
1NC
2RxD
3TxD
4NC
5GND
6NC
7RTS
8CTS
9NC
1DCD
2RxD
3TxD
4DTR
5GND
6DSR
7RTS
8CTS
9NC
Instrument
Connector
(DB9-Pin)
Computer(DTE)
Connector
(DB9-Pin)
Figure9 SerialCable Wiring Diagram