3-4
Measurements and Sourcing Voltage
Model 6487 Reference Manual
SCPI programming
SYSTem:AZERo[:STATe] <b>
Sending this command over the bus does not update the display while in remote. To verify
the AZERo state, send the query. The displayed autozero state will be updated when the
instrument is placed back in local.
Programming example
The following examples enable or disable the autozero feature:
SYST:AZER ON
' Enable autozero.
SYST:AZER OFF
' Disable autozero.
SYST:AZER?
' Query autozero. 1=on, 0=off
Zero check and zero correct
Zero check
When zero check is enabled (on), the input amplifier is reconfigured to shunt the input sig-
nal to low with the input impedance (
klqb
The ZCHK key toggles zero check on and off. If zero check is enabled
(“ZEROCHK” message displayed), press ZCHK to disable it.
From the front panel, enable/disable zero check by pressing the ZCHK key (ZEROCHK
message displayed). Refer to
for bus commands.
klqb
Leave zero check enabled when connecting or disconnecting input signals.
Figure 3-1
Equivalent input impedance with zero check enabled
Table 3-3
SCPI commands — autozero
Command
Description
Default
SYSTem
:AZERo
[:STATe] <b>
SYSTem Subsystem:
Enable or disable autozero.
ON
C
IN
Input
R
IN
510
Ω
||200nF .......... 2mA, 20mA
50k
Ω
|| 2nF.............. 20mA, 200
μ
A
3.5M
Ω
|| 120pF ....... 200nA, 2
μ
A
11M
Ω
|| 100pF ........ 2nA, 20nA
