Adding axis data and storing in a new column in CSV

Hello Rupok,

Which device example are you using. LM4F or TM4C123?

Regards
Amit

Hi Amit
I am using EK-LM4f232H5QD evaluation board
Regards
Rupok

Hi Amit

Now I am getting this output in log file.

AccelX(.01g)	AccelY(.01g)	AccelZ(.01g)	rval	Ext. Temp(.1C)	Int. Temp(.1C)	Current(100uA)
0	-3	103				18580
-25	-5	91				18580
-22	-6	93				18580
-23	1	93				18580
-43	4	103				18580
-44	0	92				18580
-34	3	80				18580
-33	1	87				18580
-26	0	102				18580

I have made following change in "ProcessDataItems(tLogRecord *pRecord) function at acquire.c file

//
// Process the accelerometers. These will be processed and stored in
// units of 1/100 g.
//

for(uIdx = LOG_ITEM_ACCELX; uIdx <= LOG_ITEM_ACCELZ; uIdx++)
{
//
// Check to see if this item should be logged
//
     if (uIdx ==LOG_ITEM_ACCELX)
     {
         if((1 << uIdx) & ulSelectedMask)
         {
           long lAccel;
           lAccel = (((long)g_ulADCData[uIdx] - 2047L) * 1000L) / 4095L;
           accelx = lAccel;

          pRecord->sItems[uItemIdx++] = (short)lAccel;
          }

     }
    if (uIdx ==LOG_ITEM_ACCELY)
   {
        if((1 << uIdx) & ulSelectedMask)
        {
           long lAccel;
           lAccel = (((long)g_ulADCData[uIdx] - 2047L) * 1000L) / 4095L;
           accely = lAccel;
           pRecord->sItems[uItemIdx++] = (short)lAccel;
         }
    }
        if (uIdx ==LOG_ITEM_ACCELZ)
       {
            if((1 << uIdx) & ulSelectedMask)
            {
               long lAccel;
              lAccel = (((long)g_ulADCData[uIdx] - 2047L) * 1000L) / 4095L;

             pRecord->sItems[uItemIdx++] = (short)lAccel;
        }

}

rval = _IQmag(accelx,accely);

pRecord1->bItems = (short)rval;
////////////////////////////////////////////////////////////////////////////////

I have also added one column called "rval" in USBStick.c file and also added the following in USBStick.c file:

ulBufIdx += usnprintf(&cBuf[ulBufIdx], sizeof(cBuf) - ulBufIdx,
                                                                          ",%d", pRecord1->bItems);

/////////////////////////////////////////////////////////////////////////////////////////////

In qs-logger.h, I have added a new structure "tLogRecord1" with element "bItems".

typedef struct
{

short bItems;

} tLogRecord1;

////////////////////////////////////////////

Problem I am facing now is--In the column "Current" , if you see, the data is "18580". During debugging, I see no change in value for "bItems" . In  addition, the program does not execute this equation "rval = _IQmag(accelx,accely);" in acquire.c file.

Hope, I am able to make you understand about the problem I am facing. Can you suggest me anything.. please

Regards

Rupok

I have also added the following line in acquire..c and USBStick.c file

static tLogRecord1 *pRecord1;

Thanks

Hello Rupol,

Having code snippets does not help me at all. If you have the complete CCS project with instructions, I may be able to help you better. Please do expect upto week of delay as it is not easy for me to switch my test rigs.

Regards
Amit

Hi Amit

I managed to solve that problem. Thanks for your time.

I need another suggestion. Can you please tell me, how can I get the velocity from acceleration. What would be the suitable formula? I know the basic one like:

V = Vo + a * t ; where Vo: initial velocity, a: acceleration,t: time

Hello Mohammed,

You can measure time using timer ticks.e.g periodic SysTick timer counts. At every instant of the tick you start Vo(n-1) at N-1 time to calculate Vo(n). The base assumption would be that Vo at time =T=0 is 0. So some sort of output to the user to be at rest to calibrate the application. Once 0 has been established then the user can start the use of sensors.

Regards
Amit

Thank you ...I will give a try and let you know... whats going on..

Hi Amit

After few search and study, so far I understand that  as we are getting acceleration in real time hence I don't think,  I need to multiply time each time with acceleration. So the formula could be:       

V(Present velocity) = V0 (past velocity) + acceleration

I am trying to implement this formula...but I am facing some problem is the addition is not done accurately instead the the output is multiplied by 10 with acceleration..  V0 may be taking some arbitrary value . I have initialized  both variable to zero at the top acquire.c file.

         V = V0 + accel_x;
         V  = V0;  // Present velocity becomes past velocity for later calculation    
        pRecord->sItems[uItemIdx++] =(short) V;

The output is--

AccelX	AccelY	AccelZ	Ext. Temp.
(g)	(g)	(g)	(C)
0.42	-0.01	0.42	4.2
0.4	0	0.4	4
0.39	-0.02	0.39	3.9
0.41	-0.01	0.41	4.1
0.39	0	0.39	3.9
0.4	-0.01	0.4	4
0.39	-0.02	0.39	3.9
0.4	0	0.4	4
0.39	-0.03	0.39	3.9
0.41	-0.02	0.41	4.1
0.39	-0.02	0.39	3.9
0.43	0	0.43	4.3

Here, Z-Axis is Z = sqrt (x^2+y^2), and Ext-temp is showing this--- V = V0+ accel_z    ;  which is nor correct. It is just multiplying the Z column value by 10.

As you suggested earlier ""At every instant of the tick you start Vo(n-1) at N-1 time to calculate Vo(n). The base assumption would be that Vo at time =T=0 is 0.""

can you please tell me how can I do this?

Thanks in advance.

Hello Rupok,

You need to multiply delta of the time other wise the units will not match m/s for velocity v/s m/sec2. At time 0 send a message to the user to stop the system, so that V is 0 when t is 0. Once done ensure that for every time unit the accel value is received and then velocity computed. The time unit must be a fixed time unit or atleast a unit that can be determined. Once the initial values are known then only value that changes is accel, with Vn-1 known at every Nth time step.

Regards
Amit

can you please give an example of--How to multiply the delta time and how to set V0 = 0 when t = 0
I have select 1/32 samples in qs-logger.

Thnaks in advance

Hello Rupok,

E.g. with SysTick timer. Set the timer for 100ms. When the accel=0, set a variable for time equvialent as 0. At this point the V0 is 0. Now use this as the base reference for further computations. So that when N=1, then t=100ms and V1=V0+100ms*Accel. When N=2, then
V2=V1+100ms*2*Accel and so on.

Regards
Amit

Hi Amit

Now I am facing this problem during debugging. If I move the board to get velocity the program stops here.......

//*****************************************************************************
//
// This is the code that gets called when the processor receives a fault
// interrupt.  This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
FaultISR(void)
{
    //
    // Enter an infinite loop.
    //
    while(1)
    {
    }
}

..........................................

I have changed the CLOCK_RATE from 100 to 10000 which is defined at qs-logger.c file but still this is happening.

please give me some suggestion

Hello Rupok,

You need to check the NVIC_FAULTSTAT and NVIC_FAULTADDR to identify the cause of the fault. There is an application note on www.ti.com TM4C12x web page which does a good job in describing the cause of the faults and what to look for.

Regards
Amit