night199uk - I have a couple of HALMETs and fin...
I have a couple of HALMETs and some old holding tank sensors that I believe are basically Tank Edge Moda sensors.
I found the thread here about using these; and it seems people are putting the voltages of these through a voltage divider. I don't have the capabilities to build voltage dividers here (I'm in the Bahamas). But I'm wondering if it's truely required. The Moda's are meant to give a voltage <5V (usually ~3.2-3.5V) at full. I'm thinking I can wire the moda sensors direct into one of the HALMET ADC1115 lines. Any thoughts?
https://forum.openmarine.net/showthread.php?tid=3358&pid=20134
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So I got my first sensor wired up to the tank edge moda today. I'm supplying the moda with a stable 12.2V through a 12V buck.
I got a basic HALMET example modified to just have a voltage sensor on A1.
auto a1_voltage = new ADS1115VoltageInput(ads1115, 0, "/Voltage A1");
With that, I'm getting a voltage of around -1.37867V in SignalK, and I was reading just above 2.2V on my multimeter. I'm guessing the negative is because I wired the polarity wrong on the A1 input, though I thought I had it the right way around.
What I'm interested in is the calibration factor which is currently default at 1.000.
Is it expected that I'd need to modify this calibration factor in this scenario and is there a more scientific way to calculate it than just comparing my multimeter values to what I see in SignalK?
After this I plan to modify the tank example which seems to be for a resistive sender, to use these voltage based senders, so I can eventually get a tank full/empty. Then I want to add automatic voltage calculation by storing the max/min voltages read on A1 over time and using those as the basis for full/empty.