Measurement Computing LGR-5320 Series User Manual page 19

LGR-5320 Series User's Guide
The first step in both multichannel and analog triggering is to examine the input signals. To determine trigger
validity, the FPGA can examine each input signal in one of eight ways. Refer to the following table.
Trigger type
Above-level
Below-level
Above-level-with-latch
Below-level-with-latch
Rising-edge
Falling-edge
Rising-edge-with-latch
Falling-edge-with-latch
The input signals are compared a specified signal level.
—This trigger is valid whenever the signal goes above the specified level, and stays valid
Above-level trigger
until the signal goes below the level.
In Figure 12, the channel trigger is valid during the two shaded intervals.
With the LGR-5327 and LGR-5329, whether or not this condition triggers an acquisition depends on the type of
multichannel triggering (AND or OR) and on the state of other trigger channels.

With OR multichannel triggering, the LGR-5327 and LGR-5329 triggers a scan when the signal first rises
above the threshold. If the device is ready and the condition is met, the scan is triggered.

With AND multichannel triggering, the LGR-5327 and LGR-5329 does not trigger a scan until every
specified trigger channel is valid. If all other trigger channels are valid, the device triggers an acquisition
when the signal reaches the shaded region. If some channels are not valid, however, this channel has no
effect.
—This trigger is valid whenever the signal level is below the level and stays valid until the
Below-level trigger
signal goes above the level—the opposite of above-level triggering.
With the LGR-5327 and LGR-5329, as with all multichannel trigger types, the acquisition's actual trigger
depends on the combination of this trigger with the other channels' trigger states.
Above-level-with-latch trigger—
above the threshold, and remains valid until the acquisition is complete and re-armed.
LGR-5325, LGR-5327, LGR-5329 trigger signal attributes
Slope
N/A
N/A
N/A
N/A
Rising
Falling
Rising
Falling
Trigger
Trigger Trigger
Figure 12. Above level initialization, instantaneous duration
Trigger
Trigger
Figure 13. . Below level initialization, instantaneous duration
With this trigger type, the channel becomes valid when the signal level is
Trigger
Figure 14. Above level initialization, latched duration
Duration
Instantaneous
Instantaneous
Latched
Latched
Instantaneous
Instantaneous
Latched
Latched
Trigger
Level
Level
Trigger
Trigger
Level
19
Functional Details
Initialization
Level
Level
Level
Level
Edge
Edge
Edge
Edge