Tektronix FCA3000 Programmer's Manual page 41

Command Groups
Figure 2-1: Flow diagram of IDLE and INITIATED layers.
Structure of an event-detection layer. The general structure of all event-detection
layers is identical. (See Figure 2-1.)
In each layer there are several programmable conditions, which must be satisfied
to pass by the layer in a downward direction:
Forward traversing an event-detection layer. After initiating the loop instruments,
the instrument waits for the event to be detected. You can select the event
to be detected by using the <layer>:SOURce command. For example:
ARM:LAYer2:SOURce BUS
You can specify a more precise characteristic of the event to occur. For example:
ARM:LAYer:DELay 0.1
You may program a certain delay between the occurrence of the event and
entering into the next layer (or starting the device actions when in the TRIGger
layer). This delay can be programmed by using the <layer>:DELay command.
Backward traversing an event-detection layer. The number of times a layer event
has to initiate a device action can be programmed by using the <layer>:COUNt
command. For example: :TRIGger:COUNt 3 causes the instrument to measure
three times, each measurement being triggered by the specified events.
Triggering *TRG trigger command. The trigger command has the same function as the Group
Execute Trigger command GET, defined by IEEE488.1.
When to use * TRG and GET
The *TRGand the GET commands have the same effect on the instrument. If the
instrument is in idle (not parsing or executing any commands), GET will execute
much faster than *TRG since the instrument must always parse *TRG.
FCA3000, FCA3100, MCA3000 Series Programmer Manual 2-25