6-4
IM 704210-01E
Explanation
Selecting the gate type
Select the desired gate type from the following.
• EVENT : Event gate
• TIME : Time gate
• EXTERNAL : External gate. It is not possible to set the arming function or use the external
arming signal if EXTERNAL is selected, since the external arming input terminal is shared
with the external gate input signal.
Points to note when selecting EXTERNAL
Input the external gating signal to the EXT ARM terminal on the rear panel.
• Input impedance : 10 k
Ω
(Typical *)
• Input coupling : DC
• Trigger level : TTL level
• Maximum input voltage : –8 V to 13 V (DC + AC
peak
)
• Minimum pulse width : 30 ns
• Setup time : 70 ns (in order for the gating signal to be valid, it must precede the measurement
signal by no less than 70 ns)
* Typical value is described in terms of typical of average performance. However, they cannot
be guaranteed.
(External arming
input terminal)
External gate input circuit (shared with the external arming signal)
IN
EXT ARM
(
TTL
)
+5V
10k
Ω
74LS14 or
equivalent
500
Ω
CAUTION
Never apply a voltage exceeding the maximum input voltage to the external arming input
terminal (EXT ARM IN). Damage to the terminal may result.
Setting range for the number of events
The setting range varies according to the selected sampling mode. This setting is available only
when EVENT gate is selected.
• For time stamp mode
• Period, time interval or pulse width measurement : 1 to 32,000
• Phase difference or duty ratio measurement :1 to 16,000
• For hardware histogram mode: 1 to 99,999,999
Note
Measurement of one block will be forced to end when 320 seconds (maximum sampling time) elapse
following the arming, even if the number of events specified in sampling mode has not been reached.
Setting range for gate time
The gate time can be set within the following range. This setting is available only when TIME
gate is selected.
1
µ
s to 10 s
Note
• Setting resolution varies depending on the value to be set. For details, refer to 12.2.
• Measurement of one block will be forced to end if the number of events for the block reaches the
maximum number of events for the selected sampling mode even if the preset gate time has not been
reached.
6.2 Setting the Gate Type, Sample Size and Sampling Interval