How Do I Adjust the Analog Input Rate of My FieldPoint Modules? Hardware: Compact FieldPoint>>Analog I/O Modules, FieldPoint>>Analog I/O Modules
Problem: Using the Measurement and Automation Explorer (MAX), I do not see how to set the sample rate for my Analog Input module. How can I program the sample rate? Solution: On a FieldPoint unit all sampling is on demand or per user request. First, you will need a FieldPoint controller that has a real time operating system on it as well as LabVIEW Real-Time. The [c]FP-2xxx family of controllers will have these deterministic features. In order to sample at various rates you will need to set the sample rate from within your program (such as a LabVIEW program) and deploy your code on the [c]FP controller by running the code under your target device. Since you will be executing in a real-time operating system you will be able to request your data deterministically unlike on your Host PC. Within your application you can place the FP Read.vi within a timed loop and set the period of the loop to the specific frequency at which you wish to sample. Keep in mind this needs to be within the limitations of the module you are using.  For example, the all-channel sample rate of the cFP-AI-118 is 10.42 kHz with no filtering. If you enable filtering on any channel, the all-channel sample rate is 3.45 kHz (This information is available in operating instructions for the module). Thus a FieldPoint Read within a loop that executes approximately once every .28 milliseconds will reach the maximum frequency for sampling off the cFP-AI-118 module. Related Links: KnowledgeBase 2T8APBP6: Can I Disable the Filter on the [c]FP-AI-110, [c]FP-AI-111, or [c]FP-SG-140? Attachments:
Report Date: 03/15/2006 Last Updated: 04/02/2008 Document ID: 3VEBLMQW |
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