AluminumAlloyBoats.com

welderbob wrote: ↑Fri Mar 23, 2018 10:15 am The sending units come with there fancy mounting ring. We weld a 1 1/2 NPT fitting in the tank and screw in. Generally they recommend a length about 3/4 of the depth of the tank. The sender with out the protective cover is a fuel sending unit, but the float is the same as the blackwater one. The gauge is there LED light one. They will also make this with an alarm sensor.

Start of a 300 gallon welded plastic waste tank.

We haven't had any come back.

Welderbob

kmorin wrote: ↑Fri Mar 23, 2018 12:02 pm Bob,
It looks like the float type with the stilling wells installed over the float- to allow liquids only into the well solves the black water challenges of mixed solids in the measured column? So that looks like a simple and easy to install solution?

But, on a related topic as a note about sensor signalling in general. The term analog usually means the circuit reading can be obtained by either a voltage or current signal. That is; the sensor control circuit or monitoring device- regardless if it is a display (only) or a digital (calculating) system- is powered by DC and the returned (attenuated) voltage or current is translated into a proportional 'reading' or value of the length of the measured column.

For example; the float type 12" (approx) probe shown probably has a magnetic coil in the float- and that creates a changing value in the control circuit due to the variable position on the corresponding 'measuring element' inside the non-magnetic SS tube. These units may be considered analog if they are powered by the control circuit (usually 12 or 24VDC) and the the circuit boards at the 'top/head/conversion housing' simply attenuate voltage or current. Current (milli-amperage)is common because the distance to the sensor's monitoring circuit is effected by the length of conductor distorting a voltage signal; but current (4-20mA is common) is not affected by the length of conductor.

The ultra sonics come in both analog signals and digital signaling - not all brands of all types will be sold in both types of signaling so that is why I thought you'd have to look at your Icon Touch 7 to see what types of signals are accepted? It is possible that it does in fact accept 4-20mA at 24VDC (very common industrial control loop signal) but then it may be designed for a line of proprietary products with other analog signal standards??

I've designed and built systems that take 4-20mA signals into PLC's from more than dozen mfg's. and all accepted the standard signals in the loop (driven control and data circuit) but some sensor manufactures' products are designed to help sell their own equipment so they have to be purchased to match a unique signal type or value.

As to digital signaling from sensors, sometimes referred to as 'smart' transmitters (not to be confused with RF devices in most uses of this term) it is most common these sensors/transmitters will have a digital conversion in their head or top housing. These types of pressure, level, temperature, flow or analytical transmitters/sensors all communicate over a 'network' type of wiring scheme. These are typically the types of physical sensors (transmitters) that will be used in a single screen display from Raymarine, Furuno types of vendors.

The only matching headache for digital sensor communications is the communications protocol or 'addressing' type used for any given device. Like matching analog standard signals, the network protocol employed in the manufacture of the digital or smart/addressable sensors needs to match for them to work with one or another brand of control/"poller"/display.

[just some notes in the overall discussion so those reading it have enough background info to make our discussion clear to the new comer to boat wiring.]

Hope you find a sensor that gives reliable service.

Cheers,
Kevin Morin
Kenai, AK