Hioki MR8827, Instruction Manual

Page: 61 / 436

56
Measurement Configuration
The sampling rate is automatically set to 1/100 of the selected timebase.
If MR8990 Digital Voltmeter Unit is installed, that channel's sampling rate is automatically set to 1/50 of
the selected timebase.
Example: When 8966 is installed as unit 1 (CH1 and CH2) and MR8990 as unit 2 (CH3 and CH4), and
the timebase is set to 1 s/div
Sampling rate of unit 1 (8966): 10 ms
Sampling rate of unit 2 (MR8990): 20 ms
To automatically set the timebase
When you press the
AUTO
key, a suitable timebase for the input signal is selected and
measurement starts. (This applies only to the Memory Function.)
Refer to “3.6 Measurement With Automatic Range Setting (Auto-ranging Function)” (p. 70).
• The timebase and sampling rate can be set independently. The sampling rate is selected depending on
the timebase setting.
• When the following timebase values are selected, displayed waveforms are compressed in the
horizontal (time axis) direction as shown.
20 ms/div → ×1/2,
10 ms/div → ×1/5
To minimize noise during measurement
If the sampling rate is too fast and the input waveform amplitude is small, the difference between
maximum and minimum values may become quite large as a result of sudden fluctuations, such
as those caused by noise. To prevent this, select a slower sampling rate or enable the module's
lowpass filter (p. 63).
Common
The data refresh rate is not allowed to exceed the maximum sampling rate of the module.
During the period when data is not updated, the same data is measured, resulting in a stair-shaped
waveform.
Even when the same signal is sampled simultaneously by two modules, the data may differ due to
differences in sampling rate, frequency bandwidth, and frequency response.
Data refresh rate for various modules
Module Max. timebase Max. sampling rate Reference
Model 8966 5 µs/div 50 ns (20 MS/s) -
Model 8967 Dependent on data refresh
setting
Dependent on data refresh
setting
Refer to “8.10.3” (p. 167).
Model 8968 100 µs/div 1 µs (1 MS/s) -
Model 8969
Model U8969
500 µs/div 5 µs (200 kS/s) -
Model 8970 Dependent on setting Dependent on setting Refer to “8.10.5” (p. 169).
Model 8971 100 µs/div 1 µs (1 MS/s) Refer to “8.10.6” (p. 172).
Model 8972 Dependent on response
setting
Dependent on response
setting
Refer to “8.10.7” (p. 172).
Model 8973 5 µs/div 50 ns (20 MS/s) -
Model MR8990 Dependent on NPLC setting Dependent on NPLC setting Refer to “8.10.8” (p. 173).
Model U8974 100 µs/div 1 µs (1 MS/s) Refer to “8.10.9” (p. 174).