2470 High Voltage SourceMeter Instrument Reference Manual
Section 4: Sourcing and measuring
2470-901-01 Rev. A /
May
2019
4-45
Source delay
When you use the instrument to source and measure, there is a delay between when the source is
turned on and when the measurement is made. The delay provides a settling time for the source.
The amount of delay time depends on the settings that are made for the source delay. You can set a
manual value, or use the autodelay setting.
Figure 69: 2470 settling and delay times
You can increase the amount of delay time by either setting a fixed amount of time or setting the
instrument to include an automatic delay. The delay can be from 0 to 10,000 seconds.
If you select an automatic source delay, the delay time depends on the selected current range.
Values for the delay times for each range are shown in the following table. The delay times shown in
the table are with source readback off and autozero off.
Current range
Voltage source
autodelay (ms)
With high
capacitance
(ms)
Current source
autodelay (ms)
With high
capacitance
(ms)
10 nA
150
300
150
300
100 nA
100
200
100
200
1 µA
3
20
3
20
10 µA
2
10
2
10
100 µA
1
10
1
10
1 mA
1
10
1
10
10 mA
1
5
1
5
100 mA
1
5
1
5
1 A
1
5
2
5
When either a source delay or autodelay is set, the delay is applied to the first source output and then
only when the magnitude of the source changes.
For high impedance and high capacitive loads, more settling time is required for the source. The
actual delay period you need can be calculated or determined by trial and error. For purely resistive
loads and at higher current levels, the programmable delay can be set to 0 ms.
The measure time depends on the selected measurement speed. For example, if the speed is set at
0.01 PLC, the measure time would be 167 ms for 60 Hz operation (0.01/60).
