Step 6. Setting-up the Trigger System
The Trigger and
Arm Model
Figure 3-4 shows the trigger and arm model for the HP E1413. Note that
when the trigger source selected is
TIMer
, or
IMM
with
INITiate:CONTinuous ON
, the remaining sources become arm sources.
Using
ARM:SOURce
allows you to specify an event that must occur in order
to start scanning.
Selecting the
Trigger Source
In order to start a measurement scan a trigger event must occur. The source
of this event is selected with the
TRIGger:SOURce <
source
>
command.
The following table explains possible choices for the
<
source
>
parameter.
Parameter Value
Source of Trigger (after INITiate:
…
command)
BUS
TRIGger[:IMMediate], *TRG, GET (for HP-IB)
EXTernal
“Trig” signal input on terminal module
HOLD
TRIGger[:IMMediate]
IMMediate
The trigger signal is always true (scan starts when an
INITiate:
…
command is received).
SCP
SCP Trigger Bus (future HP or SCP Breadboard)
TIMer
The internal trigger interval timer (must set Arm Source)
TTLTrg<
n
>
The VXIbus TTLTRG lines (<
n
> = 0 through 7)
Trigger
Timer
Trigger
Enable
Trigger
Counter
BUS
External
HOLD
IMMediate
TTLTrg<n>
SCP Trig
ARM:SOURce <source>
TRIGger:TIMer <interval>
Only while
INIT:CONT is ON
&
TRIG:SOUR is IMM
TRIGger:SOURce <source>
Internal
Trigger Signal
TRIGger:COUNt <count>
TIMer
Figure 3-4. Logical Arm and Trigger Model
86 Using the HP E1313/E1413
Chapter 3
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