Hioki MR8827, Инструкция по эксплуатации, Страница: 347 / 436

342
External I/O
17.2.3 External Sampling (EXT.SMPL)
This applies to the Memory function only.
The sampling rate can be controlled by applying an external signal.
Signal Input Procedure
1
Connect the cables for the corresponding output signals to the EXT.SMPL and GND
terminals.
2
Press the SYSTEM key to open the [Environment] sheet, and move the cursor to [EXT.
SMPL] .
3
Select whether the sampling event occurs on the rising edge (↑)or falling edge (↓) of the
waveform.
4
Input HIGH level (3.0 V to 5.0 V) and LOW level (0 V to 0.8 V) pulse waves or rectangular
waves to the EXT.SMPL terminal.
Data is sampled on the rising edge or falling edge of the input waveform. Note that the sampling
frequency is limited by the selected edge.
For proper operation, pulse width must be at least that shown in the following table.
Minimum external sampling pulse width
Setting
(EXT.SMPL)
Pulse width
When Roll Mode is [On] When Roll Mode is [Off]
t
H
t
L
t t
H
t
L
t
↑ > 5 µs > 5 µs > 10 µs > 50 ns > 50 ns > 100 ns
↓ > 5 µs > 5 µs > 10 µs > 50 ns > 50 ns > 100 ns
Voltage range High level: 3.0 V to 5.0 V, LOW level: 0 V to 0.8 V
Pulse width HIGH, LOW level: 50 ns or greater
Response frequency 10 MHz or lower
Maximum input voltage −0.5 V to 7 V
HIGH
3.0 V to 5.0 V
EXT. SMPL
LOW
0 V to 0.8 V
100 Ω
150 pF
5 V
GND
t
t
L
t
H
t
H
> 50 ns, t
L
> 50 ns, t > 100 ns
3.3 kΩ
5 V
• When a sampling signal of 5 MHz or greater is input, trigger points are delayed by 1 sample.
• When set to [Auto] or [On] , Roll Mode can be used with external sampling. However, it is set to [Off]
if the external sampling input is faster than 100 kHz to avoid degraded sampling accuracy.
• When using the 8968 High Resolution Unit, it is disabled if the anti-aliasing filter (AAF) is enabled on
the Channel screen - [Each Ch] sheet.
• When Roll Mode is set to [Auto] or [On] , externally sampled signals will not be accepted for the
following periods:
(1) 150 μs to 200 μs after the first sampling clock has been entered
(2) 2 clock periods after dead time of (1)
• When external sampling is valid, the output settings of Models MR8790, MR8791, and U8793 can not
be updated.