PLX-DAQ working but not logging data in new rows.

Projects Interfacing w/ Software on the Computer
1

Hello everyone, let me first start of by informing everyone that i am not a computer programmer or have much experience in code. I am a mechanical engineering student and am building a test rig to tune/record motions of a UAV. In order to see and record oscillations cause by the P gain of a control system i am mounting a gyroscope connected to a arduino and using PLX_DAQ to record the data.

I have every thing working except for the fact that PLX_DAQ records data in row 1 and then records over that data in row 1 with the next values. I have silenced the accelerometer and temperature variables of the sensor and recording jus the position values of the gyroscope

I am thinking that i need to put in a counter to start at the beginning of the loop but all the PLX-DAQ samples i have found do not seem to necessitate a counter.

i have included my code and would appreciate any suggestions anyone may have, thank you.

#include<Wire.h>
const int MPU_addr=0x68; // I2C address of the MPU-6050
int16_t AcX,AcY,AcZ,Tmp,GyX,GyY,GyZ;

void setup(){
Wire.begin();
Wire.beginTransmission(MPU_addr);
Wire.write(0x6B); // PWR_MGMT_1 register
Wire.write(0); // set to zero (wakes up the MPU-6050)
Wire.endTransmission(true);
Serial.begin(9600);

}
void loop(){
Wire.beginTransmission(MPU_addr);
Wire.write(0x3B); // starting with register 0x3B (ACCEL_XOUT_H)
Wire.endTransmission(false);
Wire.requestFrom(MPU_addr,14,true); // request a total of 14 registers
//AcX=Wire.read()<<8|Wire.read(); // 0x3B (ACCEL_XOUT_H) & 0x3C (ACCEL_XOUT_L)
//AcY=Wire.read()<<8|Wire.read(); // 0x3D (ACCEL_YOUT_H) & 0x3E (ACCEL_YOUT_L)
//AcZ=Wire.read()<<8|Wire.read(); // 0x3F (ACCEL_ZOUT_H) & 0x40 (ACCEL_ZOUT_L)
//Tmp=Wire.read()<<8|Wire.read(); // 0x41 (TEMP_OUT_H) & 0x42 (TEMP_OUT_L)
GyX=Wire.read()<<8|Wire.read(); // 0x43 (GYRO_XOUT_H) & 0x44 (GYRO_XOUT_L)
GyY=Wire.read()<<8|Wire.read(); // 0x45 (GYRO_YOUT_H) & 0x46 (GYRO_YOUT_L)
GyZ=Wire.read()<<8|Wire.read(); // 0x47 (GYRO_ZOUT_H) & 0x48 (GYRO_ZOUT_L)
//Serial.print("AcX = "); Serial.print(AcX);
//Serial.print(" | AcY = "); Serial.print(AcY);
//Serial.print(" | AcZ = "); Serial.print(AcZ);
//Serial.print(" | Tmp = "); Serial.print(Tmp/340.00+36.53); //equation for temperature in degrees C from datasheet

//Serial.print(" | GyX = ");
//Serial.print(GyX);
//Serial.print(" | GyY = ");
//Serial.print(GyY);
//Serial.print(" | GyZ = ");
//Serial.println(GyZ);

Serial.println("LABEL,Time,GyX,GyY,GyZ");
Serial.print("DATA,TIME,");
Serial.print(GyX);
Serial.print(",");
Serial.print(GyY);
Serial.print(",");
Serial.println(GyZ);

delay(1000);
}

2

This does not make sense. Your code appears to be more or less kosher. The only line that matters is
  Serial.println(GyZ);Which should do what you intend. You might try sending the output to the serial monitor instead, it might tell you something.
I might point out that the first red line
  Serial.println("LABEL,Time,GyX,GyY,GyZ"); is superfluous, and will likely be more trouble than it is worth, but I don't think it it is the cause of your current problem. If you must use it, it will be better in the setup than the loop.

3

Likewyse Nick_Pyner stated,
This line of code must be in Setup() Serial.println("LABEL,Time,GyX,GyY,GyZ");
That is the reason why only row1 is populated.
Or you put it in setup or you remove it out of the loop.
That should do the trick.

4

Ding ding ding GijKieken, we have a winner! Correct moving Serial.println("LABEL,Time,GyX,GyY,GyZ") out of the loop and into the setup did the trick. Thank you nick_pyner also for your observations. I tried sending the data to the serial monitor and i did get really great data. I will reduce the time delay so that i can get a much more smoother graph. Thanks agin guys! cheers!

5

I think you may still get garbage data.

Wire.requestFrom(MPU_addr,14,true);

Why are you asking for 14 bytes but only reading 6?

Pete