User manual

Chapter 3: Architecture
48
Triggering
The Analog input subsystem needs a trigger signal to start and stop
acquisition. The Trigger signal is selectable. It can be either software
command or an external pulse. External trigger is edge-sensitive. You
can select rising or falling edge to be active. If the board is set up to
start on an external trigger, all clocks will be ignored until the pulse
comes. Acquisition continues until the stop trigger comes.
Note If CV Start clock is set to continuous start/stop, the
trigger is guaranteed to start and stop acquisition at the
beginning of channel list. If CV Start is external, it’s up to
external equipment settings.
Note The PDL-MF board provides gated mode on the
external clock, when external trigger line used as a gate for the
internal/external clock. On the MF/MFS boards gated mode may
be implemented using the 8254 counter-timers.