User Manual

6.7 Triggering by Analog Signals
152
Applicable timebase range is from 20 µs to 50 ms/division.
Triggering occurs when peak voltage drops below the specified level for more
than one-half cycle. Voltage sag triggering is not available with the Model 8958
16-Ch Scanner Unit.
6.7.7 Triggering upon Instantaneous Voltage Sag at
Commercial Mains Frequency (50/60 Hz)
(Voltage Sag Trigger)
Voltage Sag Trigger ([Normal]/[Expanded] Setting)
To open the screen: Press the SET key → Select with the SUB MENU keys →Trigger Settings screen
See Screen Layout (
⇒ p. 33), To set from the Waveform screen (⇒ p. 161)
.
Operating Key Procedure
1
CURSOR
Move the highlight cursor to a trigger number to
be set.
For the [Normal] setting, match the number of the
channel to which the trigger applies.
2
Select the trigger type.
CURSOR
Move the cursor to the [Type] item.
F1 to F8
Select [Drop] (Voltage sag).
3
Select a channel (only with the [Expanded] setting).
CURSOR
Move the cursor to the [Ch] item.
F1 to F8
Select a channel to which the trigger applies.
4
Select the trigger level.
CURSOR
Move the cursor to the [Level] item.
F1 to F8 or
SCROLL
Specify the trigger threshold voltage (instanta-
neous value).
5
Set the mains frequency to be measured.
CURSOR
Move the cursor to the [Freq] item.
F1 to F8
Select either choice.
6
Set the event count (as occasion demands) (⇒ p. 143).
(only with the [Expanded] setting)
When using the Memory function, or when using the Recorder func-
tion with [Timing] set to [Start & Stop]
Set the trigger to Start or Stop (⇒ p. 145).
50Hz 50-Hz mains frequency
60Hz 60-Hz mains frequency
1
280 V
-280 V
Trigger Level
T
1/2 Cycle
Trigger No.
23 4 5 6
Setting Example
Apply a trigger if a 60-Hz mains fre-
quency input signal, nominally
about 240 Vrms (340 Vpeak),
drops below 198 Vrms (280 Vpeak)
No.1
Type ......... Drop
Ch............. 1-1(Unit 1-Channel 1)
Level......... 280 V
Parameters
Freq.......... 60Hz
Event........ 1
If trigger criteria are already met when you press the START key, no triggering
occurs. After the criteria have ceased to be met, triggering occurs when the crite-
ria are again met.