1 Topic by freds (edited by freds 22-06-2021 20:11:06)

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Topic: Engine sensor hub for older diesel bus

I have an older 40ft diesel bus that is configured as RV/Motorhome/Caravan and want to drive a RealDash electronic display.

I use one wire sensors all the time so I am really familiar with these devices and will be using them for temperature monitoring with ds18b20 sensors.

I will also be using one wire for MAX31850K Thermocouple Amplifier for turbo inlet temperature sensing. Does the one wire interface support this device?

Most after market RPM gauges are interfaced to a signal connector on the alternator which in the case of my bus output's 213HZ at 600RPM to 833HZ at 2400RPM.   The signal is a half sign wave positive voltage peaking around 19 volts on a 24v system.

Can I get an example logic blocks for this function?

For pressure sensing I am using automotive 5v sensors that output a voltage level between 0.5 and 4.5 volts. I will be using 30, 60, 100 and 150 psi sensors.

Can I get an example logic block for this function also?

Marketing note: Our yachting brethren are buying modern electronics that speak the NMEA 2000 can bus protocol and desire to monitor their engines. There are sensor hub gateways out there, but they cost $500.00 - $800.00US for just the hub.

Thanks

2 Reply by Konstantin, CANNY logic (edited by Konstantin, CANNY logic 24-06-2021 00:07:51)

  • Konstantin, CANNY logic
  • Konstantin, CANNY logic
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Re: Engine sensor hub for older diesel bus

I will proceed from the assumption that the questions are about CANNY 7.2 Duo.

The controller have a 1-Wire driver with ds18b20 support: https://cannylogic.com/docs/c72duo/1-wire/
It is do not support parasitic power mode (so you need a +5VDC source for sensors) and you can use only one ds18b20 device per channel, but you can attach up to 9 devices per controller simultaneously.
The MAX31850K have a slightly different data format than ds18b20. But it is not a problem to add the support of MAX31850K in firmware for free.

The best and most precised way to calculate the input frequency is using of pulse width meter function of IO-channel driver: https://cannylogic.com/docs/c72duo/io/# … ulse_width
The 19 volts on a 24v is OK for input if the controller's power supply is >=19V.

You can find some information of ADC usage here: https://cannylogic.com/docs/c72duo/adc/
It is 12-bit 0-32V ADC input, so you can measure the input voltage with ~ 8 mV resolution.
You can use a MAP function block https://cannylogic.com/docs/fbd/converters/map/ to convert If voltage-to-psi characteristic of your sensor have a linear characteristic. Or you can use piecewise linear approximation if the characteristic is not linear. It is pretty easy. I will explain how to do this if required.

It will be efficient to start creating a CannyLab diagram yourself. And if you get stuck then please write a new message with your question and attach your diagram to it.

Thank you for your marketing note! It is possible that compliance with maritime standards significantly affects the cost.

UPD: typos

Konstantin, CANNY logic's Website

3 Reply by freds

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Re: Engine sensor hub for older diesel bus

Konstantin, CANNY logic wrote:

Thank you for your marketing note! It is possible that compliance with maritime standards significantly affects the cost.

I don't think that affects private owners. There are a number of posts on github of people rolling there own.