question

mmosberg avatar image
mmosberg asked

Venus GX, temperature sensor issues

I have made myself two temperature probes out of LM355 sensors. When I connect to Venus GX the message "Reversed polarity" is displayed and there is no temperature reading. If I change the polarity on the terminal on the Venus GX the message "Not connected" is displayed. Any experience or help on this issue?


I have one sensor attached to the generator in my boat and the other one on the hot water boiler. Just for monitoring in my boat.

Venus GX - VGX
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9 Answers
klim8skeptic avatar image
klim8skeptic answered ·

Some sites give the wrong pinout.


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mmosberg avatar image
mmosberg answered ·

I used this. Adjust/1 not connected. I dont understand why my GX either says reversed polarity or "not connected" if I try to fix the polariry.




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klim8skeptic avatar image klim8skeptic ♦ commented ·

^This is bad^.

Try this pinout.

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lm335-pinout.jpg (16.5 KiB)
mmosberg avatar image mmosberg klim8skeptic ♦ commented ·

Will give it a try and revert.

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gnagflow avatar image gnagflow mmosberg commented ·

have you had success anyway? I have the same problem.

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Mark avatar image Mark klim8skeptic ♦ commented ·

Ok so heres a weird one! Hopefully someone can help as I'm loosing my will lol.

I have my temperature reading on vx no problem but...... as temp up the reading on vx goes down and if I cool the sensor the reading on vx goes up??? If i swap the terminals around I get either the disconnected or reverse polarity or unknown message.

Any help ideas greatly appreciated

Thanks

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paddy-bloomer avatar image paddy-bloomer klim8skeptic ♦ commented ·

I have the same problem. reverse polarity or not connected message. I have tried both pinouts can't make it work any way.

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klim8skeptic avatar image klim8skeptic ♦ paddy-bloomer commented ·

Just check that you are using an LM335 sensor. The pinout I posted above is correct.

You only need to connect the + and - pins to the venus/cerbo. Apparently you can change any temp offset via settings within venus/cerbo remote console (setup).

Good luck.

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paddy-bloomer avatar image paddy-bloomer paddy-bloomer commented ·


i cant get any where with lm335 . Ijust bought an expensive vctron temperature sensor to se if i can make it work

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paddy-bloomer avatar image paddy-bloomer paddy-bloomer commented ·

expensive victron one works perfect

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Charles Gibbs avatar image Charles Gibbs klim8skeptic ♦ commented ·
@klim8skeptic Even A few years down the line it is still the same pinout, Thank you for this it helped me out as well.


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mmosberg avatar image
mmosberg answered ·

Here is a picture of my remote GX console stating "Reverse polarity" for both sensors.


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mmosberg avatar image
mmosberg answered ·

It worked! Klim8sceptic's pinout is correct!


20200423-133716.jpg (362.5 KiB)
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s-v-simbora avatar image
s-v-simbora answered ·

Seeing that you guys have experience with the temperature sensors on the VGX, I was wondering if you would be able to help me:

I'm thinking of controlling my 12V hot water heater by my VGX. I'll use one of the temperature inputs to read the temperature of the water, and then use Relay1 or 2 to switch the heater on and off.

Would this be possible?

Can I configure the relay to see the temperature input but also only start the heater if the SOC (state of charge) of the battery is higher than a certain value?

Thanx!

Philip

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bobface avatar image bobface commented ·

This also interest me. Especially the part about starting the heater when the battery is fully charge or at specific value.


I have EasySolar 48/3000/35-50 2xMPPT 150/35. I already order VGX and SSR relay. I know it might work but don't know how to configure

Thanx



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manta avatar image
manta answered ·

Which sensor victron uses? There are different LM335 sensors. The DZ calibrated in Celsius and LM335Z calibrated in kelvin. Ant there are other differences. Does anybody know which sensor is in the Original Victron sensor? (Which obviously is too expensive)

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manta avatar image
manta answered ·

Bought original LM335 (digikey) sensor, still no output its reverse polarity or 4.98v and no value. Do i need to put a resistor between the signal. Cant open the Victron sensors. (Have 2 working). Any ideas? I bought 3 different LM335,s so going the Victron sensor route is maybe better.

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manta avatar image
manta answered ·

This is a picture of the last sensor. Clearly my pinout is different as i used the datasheet, will try to change pinout first.

pxl-20230805-1000160892.jpg


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manta avatar image
manta answered ·

Pinout was strangely enough, wrong on the datasheet of the ST semiconductor LM355, if you use the picture above. I use the 2 most right leads. Sensor works great now.

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