Agilent Technologies 33220A User Manual page 221

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Chapter 4 Remote Interface Reference
Frequency Sweep Commands
TRIGger:SOURce {IMMediate|EXTernal|BUS}
TRIGger:SOURce?
Select the source from which the function generator will accept a trigger.
The function generator will accept an immediate internal trigger,
a hardware trigger from the rear-panel Trig In connector, or a software
(bus) trigger. The default is IMM. The :SOUR? query returns "IMM",
"EXT", or "BUS"
• When the Immediate (internal) source is selected, the function
generator outputs a continuous sweep at a rate determined by the
sweep time specified (SWE:TIME command) plus 1 ms.
• When the External source is selected, the function generator will
accept a hardware trigger applied to the rear-panel Trig In connector.
The function generator initiates one sweep each time Trig In receives
a TTL pulse with the edge polarity specified by the TRIG:SLOP
command (see page 221). Note that the trigger period must be greater
than or equal to the specified sweep time plus 1 ms.
• When the Bus (software) source is selected, the function generator
initiates one sweep each time a bus trigger command is received.
To trigger the function generator from the remote interface (GPIB,
USB, or LAN), send the *TRG (trigger) command. The front-
panel key is illuminated when the function generator is waiting
for a bus trigger.
• The APPLy command automatically sets the trigger source to
Immediate (equivalent to TRIG:SOUR IMM command).
• To ensure synchronization when the Bus source is selected, send the
*WAI (wait) command. When the *WAI command is executed, the
function generator waits for all pending operations to complete before
executing any additional commands. For example, the following
command string guarantees that the first trigger is accepted and the
operation is executed before the second trigger is recognized.
TRIG:SOUR BUS;*TRG;*WAI;*TRG;*WAI
• You can use the *OPC? (operation complete query) command or the
*OPC (operation complete) command to signal when the sweep is
complete. The *OPC? command returns "1" to the output buffer when
the sweep is complete. The *OPC command sets the "Operation
Complete" bit (bit 0) in the Standard Event register when the sweep
is complete.
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