Hi everyone.
I tried to search within forum / Github repo(s) for a solution but could not come up with one yet.
I am truly a beginner with microcontrollers but I have managed to wire
Load Cell =>
HX711 =>
Arduino Mega so I have been able to measure loads after calibration.
Now I am trying to wire Load Cell => Olimex ADS1220 => Arduino MegaMy project goal would be to get data rate of 1000sps for my project which would be used in Physiotherapy/Sports to measure knee extension torque output against time (usually intervals like 50ms, 100ms, 150ms, 200ms etc. being used).With current wiring / code I just seem to get arbitrarily jumping values, no matter if I change to lower gain and/or data rate => No response to load cell tension/pressure.
For some reason I think I have issue with wiring in overall(?)
Currently my sample code has been:
#include <ADS1220_WE.h>
#include <SPI.h>
#define ADS1220_CS_PIN 7 // chip select pin
#define ADS1220_DRDY_PIN 6 // data ready pin
ADS1220_WE ads = ADS1220_WE(ADS1220_CS_PIN, ADS1220_DRDY_PIN);
void setup() {
Serial.begin(9600);
if (!ads.init()) {
Serial.println("ADS1220 is not connected!");
while (1);
}
ads.setCompareChannels(ADS1220_MUX_1_2);
ads.setGain(ADS1220_GAIN_128);
ads.setOperatingMode(ADS1220_NORMAL_MODE);
ads.setDataRate(ADS1220_DR_LVL_6); // Goal would be to get 1000sps, hence level 6
ads.setVRefSource(ADS1220_VREF_REFP1_REFN1);
ads.setVRefValue_V(5.0);
ads.setLowSidePowerSwitch(ADS1220_SWITCH);
}
void loop() {
Serial.println(ads.getVoltage_mV(), 3);
delay(500);
Current wiring as follows: Load Cell | ADS1220 |
Red (Excitation +) | IN0 |
Green (Signal +) | IN1 |
White (Signal -) | IN2 |
Black (Excitation -) | IN3 |
Load Cell GND wire has been attached to Arduino Mega GND (At least load cell instructions say it is GND wire)
ADS1220 | Arduino Mega |
AVDD | Pin 5V |
VDD | Pin 5V |
CS# | Pin 7 |
DRDY# | Pin 6 |
DOUT | Pin 50 |
DIN | Pin 51 |
CLK | Pin 52 |
GND | GND |
I have been unsure about two AVSS pins. I have connected them to GND on Arduino Mega but also have let them float free. This has not influenced the current issue in any way.
Load Cell specificationsBrand/Make | Pushton PSD-S1-100kg |
Full scale output | 2.0 mv/V |
Input impedance | 350 +/- ohm |
Output impedance | 350 +/- ohm |
Insulation resistance | >= 5000 |
Excitation Voltage | 5V |
Maximum Excitation | 12V |
| |
Any help for the newbie is welcome, thank you!
Excitation Voltage 5V
Maximum Excitation 12V
What does this mean? ADS-1220 works up to 5.5V no more.
Hi LubOlimex thank you for reply.
I just pasted the specifications as it is written on the load cell sheet which came with the load cell.
To be bloody honest I do not know why it has been detailed in that way since I've understood that one could use even lower excitation voltage, but the lower excitation voltage would generate less output voltage, right?
As I understand, I can't go over 5V when using Arduino Mega as excitation source, right?
Hence, hopefully I have been able to at least try out the load cell with ADS1220 and Arduino Mega without already breaking the ADS1220 board.
> As I understand, I can't go over 5V when using Arduino Mega as excitation source, right?
Yes.