How Do I Acquire Analog Signals Through SCXI Using an External Clock? Hardware: SCXI>>Custom Modules and Terminal Blocks>>SCXI-1180
Problem: I want to use an external clock to scan the analog input channels of my SCXI module. The external signal can come from another data acquisition (DAQ) device or an external system. Solution: You can achieve this task with most SCXI analog input modules. Please refer to the related links section below for links to information on specific modules. You must use an SCXI-1180 module to extend the I/O signals of the DAQ device to the front of the SCXI chassis. The external signal must follow the TTL specifications. You can connect your external signal to a programmable function input (PFI) line of your device, located on the front of the SCXI chassis. Another method is to use a signal from another DAQ device connected to the Real-Time System Integration (RTSI) bus, which is for sharing timing and control signals. The external signal is used as the scan clock. In LabVIEW, you can use the example Analog Input Operation with External Sample Clock, except you need to use a list with SCXI channels. Please refer to the related links below for guidelines on using SCXI channel strings. You also must specify a PFI or RTSI line for the external scan clock, which is set in the clock source parameter of the AI Clock Config VI.In LabVIEW 7.x or earlier, refer to Chapter 9, SCXI Signal Conditioning, of the LabVIEW Measurements Manual (linked below) for more information about the basic concepts of signal conditioning, the setup procedure for SCXI hardware, the hardware operating modes, the procedure for software installation and configuration, the special programming considerations for SCXI in LabVIEW, and some common SCXI applications. In LabVIEW 8.0 or later, refer to the LabVIEW Help. Related Links: KnowledgeBase 2BA2RBWH: SCXI-1140 and External Scan Clock KnowledgeBase 09BCB3NI: How Do I Set the SCXI-1140 for External T/H (Track and Hold) in LabVIEW? KnowledgeBase 2ALBUHPQ: How Can I Use an External Scan Clock with My SCXI-1540, or Other Simultaneous Sample and Hold SCXI Module? KnowledgBase 065GM6NI: Valid SCXI Channel String Arrays under LabVIEW Product Manuals: LabVIEW Measurements Manual Attachments:
Report Date: 06/02/2003 Last Updated: 10/24/2006 Document ID: 2Y12RJZW |
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