Model 2450 Interactive SourceMeter® Instrument Reference Manual
Section 2: General operation
2450-901-01 Rev. B/September 2013
2-111
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 auto delay.
Figure 58: Model 2450 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 4 seconds.
If you select an automatic source delay, the delay time depends on the selected range. Values for the
delay times for each range are shown in the following table.
Current range Voltage source
autodelay (ms)
With high
capacitance
(ms)
Current source
autodelay (ms)
With high
capacitance
(ms)
10 nA
50
100
50
100
100 nA
50
100
50
100
1
µ
A
3
20
3
20
10
µ
A
2
10
2
10
100
µ
A
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
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).
