Academic Company Events NI Developer Zone Support Solutions Products & Services Contact NI MyNI

Document Type: Example Program
NI Supported: Yes
Publish Date: Sep 6, 2006

Continuously Acquire and Graph Data with an External Scan Clock

1 ratings | 2.00 out of 5
Print

Downloads

Filename: cont_acq&graph_extscanclk.zip
Requirements: View

This virtual instrument (VI) uses an external scan clock to continually retrieve data from one or more analog input (AI) channels. This VI only works on devices to which you can externally connect a scan clock signal. This is a buffered acquisition, meaning that the data is stored in an intermediate memory buffer after it is acquired from the data acquisition (DAQ) device. Data is retrieved from the buffer and displayed on the graph. For simplicity, this VI uses AI Start.vi to configure the scan clock. However, for different types of connections on E Series devices (other than the default device), a clock source string specification is necessary. For this specification, you must expand AI Start.vi into its Advanced subVIs.
You can use the VI in this example program document when you want to supply your own scan clock to continuously acquire data.

INSTRUCTIONS:
1. Enter the device number, channels, buffer size, and scans to read at a time.
2. Make the appropriate I/O connections as explained below.
3. Run the VI.
4. The scan backlog lets you know if the VI is reading data from the software buffer fast enough to keep up with the rate at which the device is writing data to that buffer.

KEY PARAMETERS:
This VI shows how to use the intermediate analog input DAQ VIs to set up an external scan clock.

I/O CONNECTIONS:
Connect to the input channels on the I/O connector for the device to match the channels you have chosen on the front panel of this VI. For example, connect to ACH0 for analog input channel 0.

NOTE: You must scan 2 or more channels when specifying an external scan clock.

On E Series devices, connect the scan clock to PFI7/STARTSCAN. On legacy MIO devices, connect the scan clock to OUT2. On legacy MIO-16X, MIO-16F-5, and MIO-64F-5 devices, connect the scan clock to OUT2. On Lab/1200 Series devices, connect the scan clock to OUTB1. The PC-LPM-16, DAQCard-500, and DAQCard-700 are not supported by this example. To find the actual pin numbers, refer to the hardware user manual.

DAQ VIs USED:
AI Config.vi, AI Start.vi, AI Read.vi, AI Clear.vi.

Requirements


Filename: cont_acq&graph_extscanclk.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)

 
1 ratings | 2.00 out of 5
Print

Reader Comments | Submit a comment »

 

Legal
This example program (this "program") was developed by a National Instruments ("NI") Applications Engineer. Although technical support of this program may be made available by National Instruments, this program may not be completely tested and verified, and NI does not guarantee its quality in any way or that NI will continue to support this program with each new revision of related products and drivers. THIS EXAMPLE PROGRAM IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND AND SUBJECT TO CERTAIN RESTRICTIONS AS MORE SPECIFICALLY SET FORTH IN NI.COM'S TERMS OF USE (http://ni.com/legal/termsofuse/unitedstates/us/).