Keithley 6487 Reference Manual

D-4 IEEE-488 Bus Overview Model 6487 Reference Manual
Figure D-1
IEEE-488 bus configuration
Bus lines
The signal lines on the IEEE-488 bus are grouped into three different categories: data
lines, management lines, and handshake lines. The data lines handle bus data and com-
mands, while the management and handshake lines ensure that proper data transfer and
operation takes place. Each bus line is active low, with approximately zero volts represent-
ing a logic 1 (true). The following paragraphs describe the operation of these lines.
DEVICE 1
ABLE TO
TALK, LISTEN
AND CONTROL
(COMPUTER)
DEVICE 2
ABLE TO
TALK AND
LISTEN
2182
DEVICE 3
ONLY ABLE
TO LISTEN
(PRINTER)
DEVICE 4
ONLY ABLE
TO TALK
DAV
NRFD
NDAC
IFC
AT N
SRQ
REN
EOI
DATA BUS
DATA BYTE
TRANSFER
CONTROL
GENERAL
INTERFACE
MANAGEMENT
DIO 1–8 DATA
(8 LINES)
HANDSHAKE
BUS
MANAGEMENT
TO OTHER DEVICES
(6487)

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%