Keithley 6485 User Manual

F-4 IEEE-488 Bus Overview Model 6485 Picoammeter Instruction Manual
Figure F-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
6485

Keithley 6485 Specifications

General

Model	Keithley 6485
Category	Picoammeter
Input Impedance	>10^14 Ohms
Voltage Burden	<200µV
Accuracy	0.4% of reading
Voltage Source Range	Not Applicable
Voltage Source Resolution	Not Applicable
Voltage Source Accuracy	Not Applicable
Interface	IEEE-488
Power Requirements	100V to 240V AC, 50/60Hz
Dimensions	89 mm high x 214 mm wide x 369 mm deep (3.5 in x 8.4 in x 14.5 in)