I have devised a circuit in which I am getting a pressure reading from a Dwyer 616kd-11-v Transducer with a Range of 0-500Pa, I am powering this with a 5v Power Supply and it shares a common ground to the Raspberry Pi. My ADC converter is a 16 Bit ADS1115 By Texas Instruments. I have connected the transducer and I am getting a reading which is similar to that I am getting on another External Airflow Pressure meter.
The problem is as soon as the Pressure reaches 324Pa or more the Reading in my Python Shell freezes at 324 and does not change until the value has dropped below 324Pa. The Transducer has a range of upto 500Pa meaning it should be able to read upto this value?
I will attach the code I use for this below and will include my basic circuit connections.
Full Code:
import time
import board
import busio
from adafruit_ads1x15.single_ended import ADS1115
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
Transducer = 17
GPIO.setup(Transducer,GPIO.IN)
i2c = busio.I2C(board.SCL,board.SDA)
adc = ADS1115(i2c)
while True:
r0 = adc[0].value
r1 = adc[1].value
ADC_Value = r0*0.01525878906
input_value = GPIO.input(Transducer)
time.sleep(0.5)
print("GPIO17: ", (input_value))
print("AIO: ", (r0))
print("AI1: ", (r1))
print("Pressure: ",(ADC_Value),"Pa")
Connections the Vdd of the ADC converter has a 0.1uF capacitor with one end to GND and other end to Vdd.
Thanks!!
From the datasheet (http://www.dwyer-inst.com/PDF_files/P_616KD.pdf) it looks like the supply voltage should be 16-36V DC.
I think this will give you a 0-10V output under your current set-up. If you want a 0-5V output, you should connect the output pins 3 and 4 together. You need to make sure you can measure this voltage range on the ADS1115. The default range is only +-4.096V, so you will need to set the gain to its lower settings to read up to +5V.
