Section 3: Functions and features
2606B System SourceMeter® Instrument Reference Manual
3-48
2606B-901-01 Rev. B / May 2018
LAN triggering overview
Triggers can be sent and received over the LAN interface. The 2606B supports LAN extensions for
instrumentation (LXI) and has eight LAN triggers that generate and respond to LXI trigger packets.
Understanding hardware value and pseudo line state
LAN triggering is similar to hardware synchronization except that LXI trigger packets are used instead
of hardware signals. A bit in the LXI trigger packet called the hardware value simulates the state of a
hardware trigger line. The 2606B stores the hardware value of the last LXI trigger packet that was
sent or received as the pseudo line state.
The stateless event flag is a bit in the LXI trigger packet that indicates if the hardware value should be
ignored. If it is set, the 2606B ignores the hardware value of the packet and generates a trigger event.
The 2606B always sets the stateless flag for outgoing LXI trigger packets. If the stateless event flag is
not set, the hardware value indicates the state of the signal.
Changes in the hardware value of consecutive LXI trigger packets are interpreted as edge transitions.
Edge transitions generate trigger events. If the hardware value does not change between successive
LXI trigger packets, the 2606B assumes an edge transition was missed and generates a trigger
event. The following table illustrates edge detection in LAN triggering.
LXI trigger edge detection
Stateless event
flag
Hardware
value
Pseudo line
state
Falling edge
Rising edge
0
0
0
Detected
Detected
0
1
0
-
Detected
0
0
1
Detected
-
0
1
1
Detected
Detected
1
-
-
Detected
Detected
Set the LAN trigger mode to configure the edge detection method in incoming LXI trigger packets.
The mode that is selected also determines the hardware value in outgoing LXI trigger packets. The
following table lists the LAN trigger modes.
LAN trigger modes
Trigger mode
Input detected
Output generated
Notes
Either edge
Either
Negative
Falling edge
Falling
Negative
Rising edge
Rising
Positive
RisingA
Rising
Positive
Same as Rising
RisingM
Rising
Positive
Same as Rising
Synchronous
Falling
Positive
Same as SynchronousA
SynchronousA
Falling
Positive
SynchronousM
Rising
Negative
The programming example below illustrates how to configure the LAN trigger mode.
-- Set LAN trigger 2 to have falling-edge mode.
lan.trigger[2].mode = lan.TRIG_FALLING