Keithley 6485 User Manual

Model 6485 Picoammeter Instruction Manual Measurement Concepts 2-13
Figure 2-8
Floating measurements
Zero check and zero correct
Table 2-3 lists the display messages associated with zero check and zero correct. The
two-character message is displayed along with the reading.
Zero check
When zero check is enabled (on), the input amplifier is reconfigured to shunt the input sig-
nal to low as shown in Figure 2-9.
From the front panel, enable / disable zero check by pressing the ZCHK key. Refer to
Table 2-4 for bus commands.
Leave zero check enabled when connecting or disconnecting input signals.
Table 2-3
Display messages for zero check and zero correct
Display
Message
Zero Check Zero Correct
ZC On Off
ZZ On On
CZ Off On
20V
R
1
20V
A
+
–
R
2
6485
Picoammeter
R
3

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)