jeffryk avatar image
jeffryk asked

GX Tank 140 with Wema/Kus S3U Sensor

I am trying to get a GX Tank 140, plugged into a Cerbo to properly display water tank data using the currently installed Wema/Kus S3U. The data-sheet can be found here:

The Cerbo properly sees the GX Tank, displays all four ports,

It appears that my tactical error was that my current onboard tank sensors are not compatible with the GX Tank. I am surprised since they are standard resistance sensors. I have seven onboard tank sensors all the same brand and style. Is there anyway to convert the currently installed tank sensors to work with the GX Tank?



tank monitor
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3 Answers
jeffryk avatar image
jeffryk answered ·

Another way to solve my problem would be if I could get more than 4 resistive sensors into the Cerbo somehow.

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mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi @jeffryk , see my answer here, thats really the best/only solution (use a GX Tank 140 and use different tank senders for the last couple of tanks).

The problem you're having with a resistive sender and the GX Tank 140, is that the GX Tank 140 isn't made for resistive senders. Its made for voltage (0-10V) or current (4-20mA) senders.

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ainslie avatar image
ainslie answered ·

Hi @mvader (Victron Energy)

What is the solution other than buying a different interface or sensor. We purchased the GX Tank 140 based on the details provided by Victron. No where does it say not compatible with resistive sensors. Infact it is implied based on the name and marketing.

Please provide a solution that does not require the purchase of a different victron adapter worth $350 USD or replacing the already installed sensors.


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Trevor Bird avatar image Trevor Bird commented ·
@jeffryk Do all seven tank senders have an analogue gauge associated with them or are they simply sitting in the tank without any other device attached to them?
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Trevor Bird avatar image Trevor Bird commented ·
@jeffryk @Ainslie the reason I ask is because if the senders have analogue gauges on them, the voltage across the sender can be used by the Tank140 as that voltage is supplied by the gauge. In the event they do not have guages on them you could either simply put a dummy guage on them and install the guage somewhere convenient to you (or hidden out of sight if you wish) or simply install a series resistor from a convenient low voltage source. If the Tank 140 wants to see a voltage representing the fluid level it is pretty easy to provide that from the resistive sender with some simple external components.

Incidently @Ainslie , nowhere in the Victron Tank140 documentation does it say or even imply that the Tank140 is for resistive senders. Unfortunately you simply bought the wrong product.

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ainslie avatar image ainslie Trevor Bird commented ·

You are correct. However it also does not state they can't be used. Which is potentially why this thread was started by @jeffryk who has the same issue along with others in other threads.

To be fair the product is called the GX Tank 140 which implies it accepts tank sensors (a lot of these in use on yachts are the resistive type) and unfortunately you can incorrectly assume it is the same as the Cerbo as I did.

To assist others it would be good if it clearly stated it can't be used with resistive tank sensors.

We are working out a solution that we can wire between the GX tank 140 and the sensor. More than happy if you have a proven method/drawing you would like to share.

I should RTFM in more detail in the future before purchasing!


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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ ainslie commented ·

Hi both,

Sorry to hear about the confusion!

Happy to improve our documentation but where exactly? Both on the product page on our website, as well as front page as well as page 1 of the documentation, it says that its suitable for 0-10V and 4-20mA.

Here page 1 of the manual:


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