Hello,
I have a problem. I can't find answer in the documentation. Anyone can tell me what's means LJM and difference between LJM Scan Rate and Timed Scan Rate ? Thank you for help.
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Hello,
I have a problem. I can't find answer in the documentation. Anyone can tell me what's means LJM and difference between LJM Scan Rate and Timed Scan Rate ? Thank you for help.
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The LJM Scan Rate is the configured scan rate (scanRate), and what was set in the eStreamStart call. This is the scan rate the T7 hardware will use.
The Timed Scan Rate is the rate the software (MATLAB) was retrieving the scans. This is calculated by the stream read loop's total number of scans divided by the total time elapsed (totalScans/timeElapsed). The closer to the LJM Scan Rate (configured scan rate), the less overhead there was in the software's stream read loop. For testing, if you were to remove / comment out the "disp" and the "for" loop with "main_tablica", you would likely see the Timed Scan Rate get closer to the LJM Scan Rate.
Ok, Thank you for your answer. I noticed this what you said. If I have big difference between LJM Scan Rate and Timed Scan Rate, Can it causes worse results (not very accurate measurations ) ? I know device have memory where save all results before send to computer. When this memory is full then device send message about this as error.
A large difference between LJM Scan Rate and Timed Scan will not affect measurement accuracy, but can indicate the software side is not keeping up with the scan rate which causes stream buffer overflows (LJME_LJM_BUFFER_FULL). When this occurs, there will be -9999 sample values to indicate the samples that were missed while the T7 was recovering from the stream buffer overflow.
If you are encountering LJME_LJM_BUFFER_FULL errors, we have a troubleshooting page on it:
https://labjack.com/support/software/api/ljm/streaming-lots-of-9999-values