Keithley 6487 Reference Manual

3-6 Measurements and Sourcing Voltage Model 6487 Reference Manual
SCPI programming — zero check and zero correct
A) SYSTem:ZCORrect[:STATe] <b>
This method to perform zero correction is consistent with the way it is performed from the
front panel. That is, zero correction is performed while zero check is enabled. The zero
correct state can be turned on and off repeatedly without requiring a new value. If no ACQ
has been performed since the most recent reset, zero is used for the ACQ value.
B) SYSTem:ZCORrect:ACQuire
The zero correct value can only be acquired while zero check is enabled and zero correct
state is off. The internal offset measured at that moment will become the correction value.
Zero correction can then be applied and zero check disabled. This acquire method makes it
convenient if you need to re-zero the instrument often.
klqb Before sending a SYST:ZCOR:ACQ command, send a SYST:ZCOR:STAT OFF
command. Failure to do so means that you have a higher chance of getting a bad
Zero Correct value, particularly if your last Zero Correction was accomplished
on a different range.
Table 3-4
SCPI commands — zero check and zero correct
Commands Description Default Ref
SYSTem
:ZCHeck
[:STATe] <b>
:ZCORrect
[:STATe] <b>
:ACQuire
INITiate
SYSTem Subsystem:
Zero check:
Enable or disable zero check. When
Zero check is on, the reading on the
display is replaced with ZEROCHK.
Zero correct:
Enable or disable zero correct.
Acquire a new zero correct value.
Trigger a reading.
ON
OFF
A
B

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%