Continuous Data Collection

Hello there,

I need to collect data from a RMC70 controller and save it. As of now I am collecting data but doesn’t all seem to make sense to me.

  1. The index value is always 0, no matter which method I try when checking it.
  2. I am getting old readings in with the new readings, I have a feeling the reason for this is because the index isn’t working correctly.
  3. When I try to slow my capture rate down I do not get old readings in with the new but between each reading it skips a few readings which isn’t a big deal to me.
  4. In the RMC tools. In plot template editor, I kind of understand it but i’m also confused with it. What exactly does the Plot Duration and Sample Interval mean. The way that I look at it is I have the Plot Duration = 2s and Interval = .001s and the max amount of samples I can get is 2000. Which makes sense to me. But I update my read way less than every two seconds so that’s where i’m lost.
  • Right now I’m fine with collecting, I have my program reading the data file until the new data appears and then printing that to a new file so that the new file has no overlap data. I also have my program adjusting the frequency at which it goes to get new data according to how much old data was in the last file.
  • I’m fine with this I just feel like there’s a better more efficient way to do this and the Plot Duration and Sample Interval really have me confused.

thank you,


Which method are you using from the help topic on Reading RMC Plots with a Host Controller?

From the data you’re getting, it sounds like you might be using Method 4, but to get continuous data with no gaps you want to either use Method 3 or just read a static plot.

Thanks for the quick reply!

Im using #3 ive tried 3 and 4.

ill give you my current conditions incase it might matter.

At first I had it all in simulation mode because at the time I had nothing I could hook it up to.
Now we have a lvdt and load cell hooked up to it. I was able to see the gaps in the data by looking through what I printed.

I also have the index print which is zero every time. which kind of makes sense to me because if you do the correct read from the upload register element 0 to as far as you need it says its supposed to reset it. I’m ok with that. but I still felt like I should be able to access the index so I tried just reading the individual element 2 or 3 I forget which one. and still get zero. in the end I’m not too worried about this but I feel like I should be able to access it and its bothering me. I’m getting the data I want, just not the index.

also could you help me with the plot duration and sample interval. im totally lost on that if you understood what I said earlier.


The plot duration does not affect anything when you are trending (Upload mode 2). The sample interval determines the time between samples.

What that means is that you have a limited amount of time between when you start the trend and when you read the sample before the plot buffer fills up (based on memory available and not plot duration). For example, if you are requesting 100 samples at a 1 ms interval, it will be 100 ms before the RMC returns any data. If the samples are requested before that, the Samples Uploaded register will return 0. After you read the first 100 samples and another 100 ms have elapsed, the next time you get valid data the index register should show 200.

Make sure you are not writing 2 to the Upload Mode register every time you read from the Dynamic Plot Upload registers. You should only write a 2 before the first read and not subsequent reads.