Keithley 6487 Reference Manual

Model 6487 Reference Manual Buffer and Sweeps 6-11
Source range
The source range will be fixed at the lowest range required to properly handle all points in
the sweep. For example, a 10-point sweep from +2V to +11 V in 1V steps will start on the
50V range and remain on the 50V range for all points in the sweep.
Sweep direction
Sweeps can go in either direction, but the STEP is an absolute value and is always posi-
tive. It can range from zero to the value of (START - STOP).
Command restrictions
While a sweep is in progress, most voltage source control commands, trigger model com-
mands, and buffer (TRACe subsystem) commands are locked out. Sending any of the
commands listed below generates the error code +840 “Not allowed with sweep on”:
SOUR:VOLT[:LEV][:IMM][:AMPL]
SOUR:VOLT:STATe
SOUR:VOLT:RANGe
ARM:SEQ1:COUN
ARM:SEQ1:SOUR
ARM:SEQ1:TIM
TRIG:SEQ1:COUN
TRIG:SEQ1:SOUR
TRIG:SEQ1:DEL
TRIG:SEQ1:DEL:AUTO
TRAC:FEED
TRAC:FEED:CONT
TRAC:POIN
TRAC:CLE
TRAC:TST:FORM
Sweep example
For a linear sweep from -25V to +25V in 5 V steps, sweep parameters would be set as
follows:
•Start: -25
• Stop: 25
• Step: 5
This sweep will have 11 points corresponding to the voltage source values -25, -20, -15,
-10, -5, 0, 5, 10, 15, 20, and 25. Changing the step to 7V results in values of -25, -18, -11,
-4, 3, 10, 17, and 24, which shows that only complete steps are executed.

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%