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Fuel Tank Level Calibration for ICON Pro RPM Gauge

Posted: Wed Feb 07, 2018 7:41 am
by jimh
FUEL TANK LEVEL CALIBRATION for ICON Pro RPM Gauge

This procedure works on older ICON Pro RPM gauges with firmware for the legacy E-TEC engines and on newer ICON Pro PRM gauges which have been initialized for use with the legacy E-TEC engines. It does not work if a newer ICON Pro RPM gauge has been initialized for G2 engines. (See note at end of article for more details.)

The ICON Pro RPM gauge has several inputs for resistive sensors or senders (often called analogue inputs or analog inputs). If you wish to monitor a tank level where the tank has a resistive sender, you can easily accomplish this with the ICON Pro RPM gauge.

In order to monitor a tank level with an ICON Pro RPM gauge, you must wire the resistive tank level sender to an analogue input to the ICON Pro RPM gauge. The input is typically provided on a loose wire in the wiring harness that attaches to the large multi-pin connector at the rear of the gauge. The details of this are provided in the ICON Pro Series INSTALLATION GUIDE. Typically the conductor marked "ANALOGUE FUEL 1 P1-6" will be used. Be careful in locating this conductor; the wire marking for "6" can appear much like an "8".

Once you have properly wired the resistive tank level sender to an analogue input of the ICON Pro RPM gauge (see NOTE below), you can configure the ICON Pro RPM gauge to use that sender to display a TANK LEVEL. You can also perform a calibration procedure. The details of these procedures are given in the ICON Pro Series OPERATING GUIDE.

All configuration of the ICON Pro RPM gauge is accomplished by the USER INTERFACE, which consists of the LCD display, the UP button, the DOWN button, and the MENU button. For advice on how to use the USER INTERFACE of an Evinrude ICON Pro RPM gauge, read the section under the heading "On-gauge Controls" in the article "ICON Gauges for E-TEC." The article is available at

ICON Gauges for E-TEC
http://continuouswave.com/whaler/reference/ICONgauges.html

To locate a particular option in the ICON Pro RPM gauge menu structure, you must navigate to the option using the USER INTERFACE controls. I have created a MAP of the menu structure which will be helpful in navigating the menus. The map is provided in an article at

Evinrude ICON Pro RPM Gauge User Interface
http://continuouswave.com/whaler/reference/ICON_Menu.html

Let us suppose you have wired the resistive tank level sender to the conductor marked P1-6 in the ICON Pro RPM gauge wiring harness. Let us further suppose that the tank level sender has a resistance range of 240 to 33 Ohms. The configuration process will be as follows:

CONFIGURE ANALOGUE INPUT FOR TANK LEVEL. From the normal operating or presentation mode, take the following path:

Presentation Mode ---> EDIT --> DATA SOURCES ---> ANALOGUE ---> P1-6

In the P1-6 submenu, choose the option FUEL. Then escape back to the Presentation Mode

GO TO THE FUEL SET UP MENU: From the normal operating or presentation mode, take the following path:

Presentation Mode ---> EDIT --> FUEL SETUP --> TANK 1

Once at this point, choose TANK SIZE ---> SET FUEL TANK 1 SIZE GALS. Set the tank capacity in the selected units to be the tank's capacity when it is full.

Escape one level.

Choose DATA SOURCE; set to US240-33 (or to whatever resistance your sender uses)

Escape one level.

Choose REMAIN SRCE; set to ENGINE

Escape one level.

When ready to perform calibration, return to this section and choose CAL SENDER. Choose the calibration method from choices:

--2 POINT
--3 POINT
--5 POINT

Note that in order to perform the calibration procedure you generally must start with the fuel tank at empty. During the calibration process you will be adding fuel to the tank in some calibrated manner so you know with precision the number of gallons. In the absence of this data you cannot really calibrate the sender. The calibration is most easily and most logically and most quickly done if you begin with the tank level at minimum or empty. Add fuel to the tank, stopping in this process when you reach the appropriate tank level based on the tank capacity, the amount of fuel added, and the calibration method chosen.

For example, if you choose the 3-POINT method and your tank capacity were 100-gallons: with the tank at or near empty, you being the calibration procedure with that level as the first point. Next, you fill the tank with 50-gallons of fuel, i.e., to half-capacity. With the tank at this level you inform the calibration procedure you are at point 2 or HALF-FULL. Next, you fill the tank to full capacity; with the tank at this level you inform the calibration procedure you are at FULL capacity. This calibrates the tank level sender for your particular tank based on the fuel in the tank during the process.

In a similar manner you can select the 2-point method; this just calibrates at empty and full. The 5-point method calibrates at empty, 1/4-full tank, 1/2-full tank, 3/4-full tank, and full tank.

NOTE: there is only a single conductor provided for the analogue inputs at the ICON Pro RPM gauge. The common conductor for these circuits is the battery negative power lead. If the tank level sender has an isolated return circuit, you can carry the tank level sender second wire back to the helm area. There you can bond the second wire of the tank level sender to the battery negative power bus. If the tank level sender has only one wire, then the tank is likely a metal tank, and the tank BONDING wire is likely already bonded to the battery negative bus at some point in the boat wiring.

NOTE: only one instrument or gauge or analogue input can be wired to the tank level sender. You cannot connect other gauges or analogue inputs in parallel at the tank level sender.

NOTE: The tank level sender must provide a varying resistance that is proportional to tank level. There are two common standards for tank level resistive senders. In North America in particular in the USA, the resistance range is usually 240-Ohms (empty) to 33-Ohms (full). In Europe and elsewhere the resistance range is usually 10-Ohms (empty) to 180-Ohms (full). Note that the proportionality of tank level and resistance is opposite in these two standards. For more information see the companion article on Fuel Sender Resistance.

NOTE: If using the ICON Pro RPM gauge with E-TEC G2 engines, use of the analogue inputs for fuel tank level will be disabled. This unfortunate loss of feature set in the ICON Pro RPM gauge is due to the preference by Evinrude to use the analogue inputs in their ICON II EST Premium control head for the fuel tank level function. As best I can determine, this preference is due to the ability of the ICON II EST Premium control head to convert the analogue input data into NMEA-2000 tank level data and broadcast it to the attached NMEA-2000 network.

Fuel Tank Level Calibration for ICON Pro RPM Gauge

Posted: Sun Feb 18, 2018 11:17 am
by jimh
In some prior discussions a method of performing the CAL SENDER procedure that is available in the ICON Pro RPM gauge has been discussed in which the actual sender is removed from the fuel tank and mechanically manipulated to various positions during the calibration process. I don't actually recommend this method for these reasons:

  • requires breaking sealed fuel tank enclosure to remove sender
  • requires working with electrical circuits while the fuel tank is being openly vented to the air by the hole from the sender access point
  • requires guessing at the sender orientation as representative of a certain level.

However, some boaters seem to find value in this method. For those boaters who plan to perform the CAL SENDER procedure by removal of the sender and mechanical manipulation of it, I can offer some advice.

The ICON Pro RPM gauge is quite slow to respond to changes in the input resistance it senses from the fuel tank level sender. Because of this, during the calibration procedure when moving the sender to a new setting for each calibration point, you must allow about 10 to 20 seconds with the sender at the new calibration point before you enter that sender position in the procedure. If you very rapidly move the sender and rapidly enter the new calibration, the results will not be as good as if you wait between data entries.

As the calibration process is normally done by actually filling the fuel tank with fuel, the fueling takes several minutes between calibration points, so the slow response of the input to change is not likely to affect calibration. When the sender is rapidly changed in a manual manipulation, the input may not respond as rapidly.

Also, use the 5-POINT option. The 5-POINT option seems to produce the best correlation between sender resistance and displayed tank level cross the whole range.

I base these recommendations on some recent bench testing I performed with an ICON Pro RPM gauge connected to an external variable resistor. I moved the input shaft of a rotary potentiometer over its 270-degree arc to the appropriate positions for the 2-POINT, 3-POINT, and 5-POINT calibrations. By waiting over 20-seconds at each new entry point and using the 5-POINT calibration, I obtained the best correlation between the display of tank level on the eight-segment grow bar display on the ICON Pro RPM gauge and the position of the potentiometer input shaft. Calibration using only the 2-POINT option seemed to produce a non-linear response from the gauge display; very small increments of potentiometer shaft movement (or very small resistance changes) caused large changes in the gauge display between the EMPTY and HALF-FULL marks of the display.