RC Refresh Rate

Technical Programming
1

Does anyone happen to know how often the RC will scan the code?

I’m trying to estimate how long something will go by saying increment the counter every loop but i don’t know how often it refreshes so therefore i don’t know how many increments i want it to count to…:mad:

Thanks in advnace

2

The 2007 & 08 RC’s execute the user code around 28-32 times per second, depending on the amount of time the code takes to execute.

3 
    if (statusflag.NEW_SPI_DATA)      /* 26.2ms loop area */
    {                                 /* I'm slow!  I only execute every 26.2ms because */
                                      /* that's how fast the Master uP gives me data. */
      Process_Data_From_Master_uP();  /* You edit this in user_routines.c */

      if (autonomous_mode)            /* DO NOT CHANGE! */
      {
        User_Autonomous_Code();        /* You edit this in user_routines_fast.c */
      }
    }

Stuff in Process_Data_From_Master_uP() will be run every 26.2ms. Same with User_Autonomous_Code() (when the robot is in autonomous).

It doesn’t vary much to matter, if you have code that makes it take longer than 26.2ms to run it, it will explode.

4

Thanks! Thats exactly what i was looking for… I thought i had seen that in the code before but when i went to look for it i couldn’t find it

5

Can we figure out the loop time for the 2009 controller or do we have to wait for the default code?

6

Based on the information I’ve been able to scrape together about the new control system, I’m not sure “loop time” is going to be a valid concept. It looks like it’ll be more like the way EasyC works: if you want to keep track of time, or do something every so often, you’ll have to use real timers.

7

Just to head off any programming headaches, the User_Autonomous_Code() function is, in fact, only run once per autonomous mode. It doesn’t even loop. It instead has a while loop in it that the execution stays in until autonomous mode ends. There’s a section in this other while loop that has the same update rate, but it’s technically incorrect to say that User_Autonomous_Code itself is run every 26.2ms.

Also, the new controller could still be running tasks in fixed time loops. At least, it’s easily possible to do so on a Labview RT controller, though there are certainly other control methods they could be using. But for measuring elapsed time, it’d certainly be easier to start a timer and watch the elapsed time value instead of trying to count loops.