Performing Single-Shot Waveform Acquisition Using an External Channel Clock

This VI acquires analog input data into a buffer in a single-shot manner, where its acquisition timing is based on a channel clock external to the data acquisition timing circuitry.

NOTE: This will only work on those devices where you can externally interface a channel clock signal.

For external channel clock-based acquisition, the channel clock must be reconfigured after calling AI Config because AI Config internally sets up the channel clock to certain default values.

Furthermore, the scan clock is disabled so that the channel clock can dictate the acquisition rate.

Determining the scan rate
* If you have one channel in your channel list, then: scan rate = channel clock rate.
* If you have more than one channel in your channel list, then: scan rate = channel clock rate / number of channels

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Signal connection instructions:
To find out the actual pin number, refer to the hardware user manual.

For E-series devices:
(external timing connection) Set the clock source code to either "PFI pin - low to high" or "PFI pin - high to low", specify which PFI pin in clock source string, and connect your clock signal to the specified PFI pin on the I/O connector.

(clock signal delivered over RTSI bus) Set the clock source code to either "RTSI pin - low to high" or "RTSI pin - high to low", specify which RTSI pin in clock source string, and connect your clock signal to the specified RTSI pin by using the Route Signal VI. (This is not done in this example to ensure simplicity.)

(clock signal from general purpose counter "GPCTR" output or Analog Trigger Circuitry output "ATCOUT") Set the clock source code to either "GPCTR output ..." or "ATCOUT ...", and specify "0" in clock source string if using a GPCTR (since this can only be done with GPCTR 0), or a blank if using ATCOUT. To program a GPCTR for square wave generation, use the Counter VIs. If using ATCOUT, use the AI Trigger Config VI to set trigger parameters. (This is not done in this example to ensure simplicity.)

For non-E-series MIO-type devices:
(external timing connection) Set the clock source code to "I/O Connector", leave clock source string blank, and connect your clock signal to the EXTCONV* pin on the I/O connector. Every falling edge will make the device take a sample.

(clock signal delivered over RTSI bus) Set the clock source code to "RTSI Connector", leave clock source string blank, and connect your clock signal to the EXTCONV* pin on the RTSI connector using the RTSI Control VI so that this device will receive the signal on a particular RTSI trigger line. Every falling edge will make the device take a sample. (This is not done in this example to ensure simplicity.)

For other devices with a channel clock (all other analog input devices not including A2xxx series):
Set the clock source code to "I/O Connector", leave clock source string blank, and connect your clock signal to the EXTCONV or EXTCONV* pin on the I/O connector. Each device differs in which edge takes a sample. Please refer to your hardware user manual for details

Requirements

Filename: 201029.zip

Software Requirements

Application Software: LabVIEW Full Development System 5.0.1
Language(s): LabVIEW

Hardware Requirements

Hardware Group: Multifunction DAQ (MIO)
Driver: Traditional NI-DAQ (Legacy)

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