Honeywell TruStability Digital pressure sensor review

R_Phoenix — Tue, 09 Nov 2021 16:55:34 GMT

Current Revision posted to Documents by R_Phoenix on 11/9/2021 4:55:34 PM

Honeywell TruStability Digital pressure sensor review

Products:

HSCDANN001PGSA5 0 to 1 psi digital output

HSCDANN005PGSA5 0 to 5 psi digital output

Test Bed:

Mbed rapid proto typing Microcontroller

Arduino Microcontroller

Product Overview:

The sensors are packaged in a nice clean hard plastic shell that provides good protection during shipment. The sensors themselves look and feel sturdy and appear to be able to handle small vibrations and shock. There are a wide verity of mounting and tube connection types as well as 3.3 or 5 volts. They are available in Analog, I2C, or SPI digital communication.

Both sensors I looked at use the SPI Bus for communications and are 5 volts powered. Note that I was not familiar with the SPI bus before this evaluation, I thought I had requested the I2C versions – but that’s OK. I learned something new as well.

Product Documentation:

The Documentation was a bit time consuming to find. Honeywell likes to create documents that encompass an entire series of product, so I had to track down and piece together all the needed information. If you have ever navigated Honeywell’s web site, it can be overwhelming at times simply trying to find a specific product and as usual, entering the part number in the search box yielded 0 results. I prefer that all the needed information is on one data sheet.

Related documents:

http://sensing.honeywell.com/index.cfm/ci_id/157751/la_id/1/document/1/re_id/0

http://sensing.honeywell.com/index.cfm/ci_id/156989/la_id/1/document/1/re_id/0

http://sensing.honeywell.com/index.cfm/ci_id/156218/la_id/1/document/1/re_id/0

After spending a few hours gathering the needed information about how to program the needed SPI interface, I constructed a small test bed to test the sensors.

Basic Layout:

This image shows the Sensor connected to my small hand pump and analog mechanical gauge. This allows me to slowly apply pressure to the sensor and I can verify the pressure with the gauge against the sensor. The LED allows me to verify that the device is being selected, as the SS line goes low when reading data from the device.

Arduino Hook up

At this point I have to admit that my evaluation failed. The reason for this is unclear but I could not get the device to produce the proper information. This might be due to the fact that I’m too unfamiliar with the SPI interface, or possibly I am missing a key bit of information about the Honeywell SPI interface. I spent several hours talking to others and discussing the data and programming on other forums and after trying several things, everyone has run out of Ideas.

I want to post my results here for anyone else thinking about using these sensors so they can see everything that I have tried. Hopefully Someone here (or possibly from Honeywell) can spot the problem. Most likely I am missing something in the hookup or programming and the device operates just fine.

One issue I thought sure was the problem was the fact that the mbed MPU is 3.3 volts and possibly was not putting the proper voltage on the SCLK line. This is why I switched over to the Ardunio MPU. This uses 5 volts instead and should produce the needed 4 volts on the SCLK line – However as you will see the results were the same.

Programming:

mBed test program:

#include "mbed.h"
#define OUT_MAX 16384
#define OUT_MIN 0
#define PRES_MAX 5
#define PRES_MIN 0

SPI spi(p11, p12, p13); // mosi - no connection, miso - connected to pin 3 of sensor, sclk connected to pin 4 of sensor
DigitalOut cs(p8); // chip Select line connected to pin 5 of sensor

Serial pc(p9,p10); // tx, rx

int main() {
    // Setup the spi for 8 bit data with a 800KHz clock rate
    spi.format(8,0);
    spi.frequency(500000);

    while(1)
    {
    // Select the device by seting chip select low
    cs = 0;
    wait_us(8);
    // Send a dummy byte to receive the contents
    int byte_1 = spi.write(0x00);
    int byte_2 = spi.write(0x00);
    int byte_3 = spi.write(0x00);
    int byte_4 = spi.write(0x00);

    float temp = byte_3<<3;
    temp = (temp*200/2047)-50;
    float psi = byte_1<<8|byte_2;
    psi = ((psi-OUT_MIN)*PRES_MAX)/(OUT_MAX-OUT_MIN);

    pc.printf("Byte 1 = %X; Byte 2 = %X; Byte 3 = %X; Byte 4 = %X; PSI = %.4f; TEMP = %.2f:\r",byte_1,byte_2,byte_3,byte_4,psi,temp);

    // Deselect the device
    cs = 1;
    wait(1);
    }
}

mbed results:

note: Byte_1 to Byte_4 are in HEX notation, PSI and TEMP are Dec

Ardunio Program:

#include <SPI.h>

// pins used for the connection with the sensor
// the other you need are controlled by the SPI library):
const int dataReadyPin = 6;
const int chipSelectPin = 7;

void setup() {
Serial.begin(9600);

// start the SPI library:
SPI.begin();
SPI.setClockDivider(128);
// initalize the data ready and chip select pins:
pinMode(dataReadyPin, INPUT);
pinMode(chipSelectPin, OUTPUT);
digitalWrite(chipSelectPin,HIGH);

delay(100);
}

void loop()
{
digitalWrite(chipSelectPin,LOW);
delay(10);

int inByte_1 = SPI.transfer(0x00);
int inByte_2 = SPI.transfer(0x00);
int inByte_3 = SPI.transfer(0x00);
int inByte_4 = SPI.transfer(0x00);

Serial.print("Byte_1 = ");Serial.print(inByte_1,DEC);Serial.print(" ");
Serial.print("Byte_2 = ");Serial.print(inByte_2,DEC);Serial.print(" ");
Serial.print("Byte_3 = ");Serial.print(inByte_3,DEC);Serial.print(" ");
Serial.print("Byte_4 = ");Serial.print(inByte_4,DEC);Serial.print(" ");

float psi = inByte_1<<8|inByte_2;
psi = (psi*5)/16384;
Serial.print("PRES = ");Serial.print(psi);Serial.print(" ");

inByte_3 = inByte_3<<3;
float realTemp = ((float)inByte_3*200/2047)-50;
Serial.print("Temp[C]= ");Serial.print(realTemp);Serial.print("\n");

digitalWrite(chipSelectPin,HIGH);
delay(1000);
}

Arduino Results:

Note: all numbers are in Decimal notation.

The Problem:

The internal temperature was close, only 3 to 4 degrees off from Ambient temperature. I assume this to be correct as it is measuring the temp of the sensor itself and not ambient air (I don’t think). So my conclusion is that the electronics will warm a bit during use. I believe the Temperature to be correct.

However the Pressure was way off. The Documentation states the digital counts should be between (or near) 0x000 with 0 pressure and 0x3FFF at MAX Pressure +/- Atmospheric. I was unable to achieve either value. In fact the most the digital count changed between 0 and 5psi was about 450 counts. Not near enough to be highly accurate.

What I have tried:

I have tried all formats, 8,0 8,1 8,2 and 8,3 as well as 16 bit vs 8 bit

I have tried reading all data in a single string instead of pinging the register 4 separate times.

I have tried all possible clock frequencies.

One thing myself and other could not find in the documentation was any mention of a specified register address that I must read first. This lead me to believe that there was none.

I have tried several different values for the OUTPUT Max and the OUTPUT Min including those listed in the documentation.

I have tried decoupling the power lines.

All of these things would affect the output data, but not make it correct.

In conclusion:

Because I was unable to test these sensors successfully I cannot comment on their stability, function, or accuracy. Currently I use the ADMS series of Honeywell Analog sensors and those work great and are Highly accurate. I can measure water levels down to 0.25” accuracy and could get it even further if I needed to. Unfortunately I was unable to test the HCS series in this application. If anyone might have ideas on what I am doing wrong, please message me and I will update this document with any new developments.

Tags: spi, pressure_sensor, honeywell, hsc, Design Resources