Analog Input Timing Signals
- Updated2024-12-11
- 1 minute(s) read
The cDAQ chassis features the following analog input timing signals.
- AI Sample Clock Signal*
- AI Sample Clock Timebase Signal
- AI Start Trigger Signal*
- AI Reference Trigger Signal*
- AI Pause Trigger Signal*
Refer to the related topic links below for more information about the configuration of these signals.
Signals with an * support digital filtering. Refer to the PFI Filters section for more information.
Refer to the AI Convert Clock Signal Behavior For Analog Input Modules section for AI Convert Clock signals and the cDAQ chassis.
Related Information
- AI Sample Clock Signal
A sample consists of one reading from each channel in the AI task. Sample Clock signals the start of a sample of all analog input channels in the task.
- AI Sample Clock Timebase Signal
The AI Sample Clock Timebase signal is divided down to provide a source for Sample Clock. AI Sample Clock Timebase can be generated from external or internal sources. AI Sample Clock Timebase is not available as an output from the chassis.
- AI Start Trigger Signal
Use the Start Trigger signal to begin a measurement acquisition.
- AI Reference Trigger Signal
Use Reference Trigger to stop a measurement acquisition. To use a reference trigger, specify a buffer of finite size and a number of pretrigger samples (samples that occur before the reference trigger). The number of posttrigger samples (samples that occur after the reference trigger) desired is the buffer size minus the number of pretrigger samples.
- AI Pause Trigger Signal
You can use the Pause Trigger to pause and resume a measurement acquisition. The internal sample clock pauses while the external trigger signal is active and resumes when the signal is inactive. You can program the active level of the pause trigger to be high or low.
- PFI Filters
You can enable a programmable debouncing filter on each PFI signal. When the filter is enabled, the chassis samples the inputs with a user-configured Filter Clock derived from the chassis timebase. This is used to determine whether a pulse is propagated to the rest of the circuit. However, the filter also introduces jitter onto the PFI signal.
- AI Convert Clock Signal Behavior For Analog Input Modules