Keithley 6487 Reference Manual

9-18 Remote Operation Model 6487 Reference Manual
RS-232 connections
The RS-232 serial port can be connected to the serial port of a controller (i.e., personal
computer) using a straight through RS-232 cable terminated with DB-9 connectors. Do
not use a null modem cable. The serial port uses the transmit (TXD), receive (RXD), and
signal ground (GND) lines of the RS-232 standard. It does not use the hardware handshak-
ing lines CTS and RTS. Figure 9-4 shows the rear panel connector for the RS-232 inter-
face and Table 9-2 shows the pinout for the connector. The connector location on the rear
panel is shown in Figure 9-3.
Figure 9-4
RS-232 interface connector
If your computer uses a DB-25 connector for the RS-232 interface, you will need a cable
or adapter with a DB-25 connector on one end and a DB-9 connector on the other, wired
straight through (not null modem). Table 9-3 provides pinout identification for the 9-pin
(DB-9) or 25-pin (DB-25) serial port connector on the computer (PC).
Table 9-2
RS-232 connector pinout
Pin number Description
1 DCD, data carrier detect
2 TXD, transmit data
3 RXD, receive data
4 DTR, data terminal ready
5 GND, signal ground
6 DSR, data set ready
7 RTS, request to send
8 CTS, clear to send
9 No connections
RTS and CTS are tied together.
DCD, DTR, and DSR are tied together.
TXD and RXD are swapped on Model 6487 and PC so
that null modem cable is not required.
9876
54321
Rear Panel Connector
RS232

Keithley 6487 Specifications

General

Type	Picoammeter/Voltage Source
Current Measurement Range	20 fA to 20 mA
Interfaces	GPIB, RS-232
Voltage Burden	< 200 µV
Input Impedance	>10^14 Ω
Power	100 V / 120 V / 220 V / 240 V
Basic Current Measurement Accuracy	0.4%