Technoversions Metermatch User manual

MeterMatch™

Overview

MeterMatch™ by TechnoVersions LLC is for making analog

gauges more accurate, or to allow you to mix and match

different gauges and senders. It can be used with many

gauges that have resistive senders - such as common fuel, oil-

pressure and temperature gauges. In addition, it allows you to

have low and/or high set-points that will trigger a bright, blinking

LED indicator to alert if the gauge exceeds normal values.

Note: If you are having trouble reading the small print of this instruction manual, go to the

TechnoVersions website and open the on-line copy. You can print it out full size.

Theory of Operation

MeterMatch is wired between your sender (sensor) and your gauge. It reads the resistance of the

sender, then based on the calibration values, sends a signal to drive your gauge to the desired

reading. It treats the input and output entirely separately, so it doesn't care if the input to the gauge is

scaled differently than the sender, or even if the sender signal has a reversed sender signal than the

gauge - it can correct for that.

To calibrate MeterMatch, you first set the sender to a known value. For example, fill your fuel tank.

Set the MeterMatch to program mode, then with Up and Dn buttons, make your gauge read what you

want for that sender value. When you are happy with that, press the Save button, and the value is

remembered in the MeterMatch. Do the same process with the sender reading a value near the other

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end of its range, and you are done. MeterMatch interpolates from these values to make the gauge

read proportionately at values above, below, and between the calibration values. If you know the

resistance of your sender, you can also calibrate to common end-values of senders, even without the

sender being at that specific resistance.

The basic process of having the gauge read properly from calibration points near each end of the

range is fine for most applications, but you can be more sophisticated if you wish. For example, what

if your fuel tank is large at the bottom, and small at the top? In this case, it won't read properly

throughout the range. MeterMatch provides two additional calibration points between the endpoints.

So, in this case, you could have an additional calibration point where the tank changes size. Another

use for these points would be if your tank is cylindrical (like a truck fuel tank) so the gauge is

inaccurate at both sides of center. Here, you can add additional calibration points (for example at

30% and 70%) and the accuracy is drastically improved

Optional Alarm Indicator

MeterMatch allows you to set a lower and higher alarm set-point. These are

set just like the calibration points (you use the Up/Dn buttons to set the

gauge to the point at which the alarm happens), but instead of affecting the

meter reading, they set a signal to turn on an optional LED. This bright LED

is programmed to flash, and can be mounted near the meter to alert the

driver to take a look at the gauge. You can use none, either, or both set-

points.

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Installation

MeterMatch is contained in a plastic enclosure that is 1.85" by 2.4" x .93". To install and calibrate it,

you will need to expose the circuit by removing the small Phillips-head screw in the bottom center of

the enclosure. Use a #1 or smaller Phillips screwdriver. Take care that the circuit board doesn't

touch any metal which could short things out, and when finally installed, make sure it is in a dry spot

that doesn't get overly hot.

It is wired by connecting to a screw-terminal strip inside. You will need a small straight-blade

screwdriver (tip width less than .11"). It accommodates wire sizes from #16 AWG to #28 AWG.

Wires on the larger end of this range, for example #18 AWG, are recommended.

MeterMatch only requires four wires, and all these signals are usually available near the back of the

gauge. The signals are:

Pin 1 +12V (switched by ignition)

Pin 2 Input signal to gauge (output from MeterMarch)

Pin 3 Output signal from sender (input to MeterMatch)

Pin 6 Ground

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Calibration

Once wired, it is necessary to calibrate your MeterMatch.

The rotary switch Ѳ positions are used as follows:

0 Normal Operation after calibration

1 High calibration point

2 Mid-high calibration point

3 Mid-low calibration point

4 Low calibration point

5 Alarm high calibration point

6 Alarm low calibration point

In addition to the terminal strip and rotary switch, you will find three push-buttons:

Up Moves the meter needle one direction

Dn Moves the meter needle the other direction

Save Stores the calibration point presently selected

Standard calibration process (sender resistance not known):

1. Set your sender to a point near one end of the value being measured (we'll start at the top in this

example, but order is unimportant).

2. Set the rotary switch Ѳ to position "1" (High Calibration Point). The LED in MeterMatch will light

up.

3. Use the Up/Dn buttons to make your gauge read the appropriate setting for the present sender

output. Depending on the gauge, the buttons may work backwards, but don't worry about that - just

make the gauge read the desired value. MeterMatch will work properly even if polarity is reversed

between the gauge and sender. Some meters are well-dampened so this process can take a little

time. It doesn't hurt to tap lightly on the gauge too.

4. Press the Save button to save this calibration point. The LED on MeterMatch will go out

momentarily to indicate that the value is being saved, and then turn back on.

Note: Calibration doesn't need to be done at the extreme high and low sensor points, but most

accuracy is achieved when near the limits of the readings.

Repeat these steps but with the sender set to a position for the other end of measurement, the rotary

switch Ѳ to "4" (Low Calibration Point), and then use the Up/Dn buttons until gauge is reading

appropriately, then press Save again.

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Finally, set the MeterMatch rotary switch Ѳ back to "0" (Normal Operation), put the cover back on,

and enjoy using your calibrated gauge.

Resetting the MeterMatch:

You can go back and reset any point using the same process, it will simply over-write the data for that

point stored previously. If you would like to erase a point (for example a point or limit you don't want

to use any more): with no power applied, set the rotary switch Ѳ to the position reflecting the point

you want to erase, hold down the Save button, then turn power on. If you want to reset the

MeterMatch to factory settings: with no power applied, set the rotary switch Ѳ to position 0, hold

down the Save button, then turn power on.

Alternate calibration process (sender resistance known):

If you know the resistance of your sender, you can use that to help do calibration. You will need to

know the sender range (end-points) in Ohms. For example the sender might be 240 Ohms () when

the reading is low, and 33 Ohms when the reading is high. If you have this data, there are two ways

that you can use it for calibration:

Method 1: Connect a resistor (available at places such as Radio Shack) of the desired value on the

MeterMatch sender input pin (pin 3) to ground, and then perform calibration at that point just as with

the standard calibration process previously shown.

Method 2: You can have MeterMatch calibrate to some internally stored resistance values. To use

these, do the following:

1. Power up MeterMatch

2. Set the rotary switch Ѳ to zero (normal operation)

3. Press and hold the Save button. The LED will illuminate.

4. While the Save button is being held down, press the Up button, the number of times shown in this

table. Each time you press the Up button the LED will blink the number of times that it has been

pressed. For example after you have pressed it twice, it will blink twice. Wait each time for the

blinking to occur. You can start over at any time by releasing the Save button.

Number of "Up" Button

Pushes

Sender Resistance Simulated

(Ohms)

1 0

2 10

3 33

4 73

5 90

6 180

7 240

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5. Release the Save button, then use the standard calibration procedure (rotary switch Ѳ to which

point you are setting, Up/Dn buttons to make gauge read the desired setting, then Save). When the

Save button is pressed (and the rotary switch Ѳ is not set to 0), MeterMatch will use the resistance

value you just entered, and then reset itself to back normal operation (measuring the connected

sender resistance).

Calibration Checking and Enhancement

Feel free to use a combination of these calibration methods. For example, you might initially calibrate

to the published resistance values of your sender, then when the opportunity comes to improve

accuracy, recalibrate a point. Using the fuel gauge, for example, recalibrate the end-point when you

run out of gas, or fill up the tank. Whenever you return to a position of the rotary dial, you can over-

write the data that was previously programmed.

Voltage Correction

Most gauges are connected to a voltage regulator in the instrument wiring so that they get a constant

voltage whether the engine is running or not. However, if this is not the case, when you calibrate your

gauge at one voltage (for example, engine not running, battery at +12.5V), when you start the vehicle

and the voltage rises (for example to +13.8V), the gauge reading might change significantly. If you

run into this, MeterMatch has an automatic voltage correction feature that corrects the reading for

different voltages. To enable this feature: (a) remove power from the MeterMatch, (b) set the rotary

switch Ѳ to position "0" (normal operating), then (c) press and hold the Up button while applying

power to the MeterMatch. Hold it for at least a second after power is applied. MeterMatch will

remember this setting in future use. If you wish to remove the voltage correction feature, repeat the

same process, but hold the Dn button rather than the Up button. Note that if you change this setting,

the gauge will need to be recalibrated with the new setting.

Installing/Programming the Alarm Indicator

The optional LED Alarm Indicator can be mounted near the gauge being controlled.

The LED is installed by drilling a 9/16" hole in the instrument panel. 12" leads are then wired to the

terminal strip in the MeterMatch. Be careful when installing the LED since the leads are not

particularly strong, and can be pulled loose from the LED. The darker of the two wires (cathode

lead) coming from the LED is installed in terminal strip pin 4, and the lighter-colored wire (anode side)

is connected to pin 5. It won't hurt anything if you accidently reverse these wires, but the LED won't

light.

Pin 4 LED negative (cathode)

Pin 5 LED positive (anode)

You can program the upper and lower alarm points with rotary switch Ѳ positions 5 and 6

respectively. Set the rotary switch Ѳ , use the Up/Dn buttons to set the desired gauge reading at

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the set-point, then press Save. MeterMatch doesn't care what value the sender is at while

programming the alarm points - it is only interested in what you make the gauge read with the Up/Dn

buttons. As a result, ensure that you have calibrated your gauge accurately (rotary switch Ѳ

positions 1-4), or your alarm will not be accurate either.

These points can also be erased using the same procedure as normal cal points. Depending on how

your gauge works, you may find that the low and high alarm set-points are reversed in operation from

what you expect. If that's the case, simply reverse the calibration (use high for low and vice-versa).

If you have more than one MeterMatch installed, you can logic "or" the LED signals so that if any of

the alarm signals become true, they will set off a single LED. Simply connect the LED positive

(anode) to any one of the MeterMatch circuits, and then connect all of the MeterMatch LED negative

(cathode) wires to the LED negative side wire.

Return Policy

If a MeterMatch unit does not work properly in your application, and is not damaged, TechnoVersions

will allow return for full refund of purchase cost, exclusive of shipping charges. Claim for such must

occur within 30 days of product shipment from TechnoVersions. Ship the unit back to

TechnoVersions along with a description of the problem and proof of purchase. TechnoVersions will

remit the refund via US Mail or PayPal (at TechnoVersions discretion) within 10 working days of

product receipt.

Limited Warranty

TechnoVersions LLC provides a limited warranty for MeterMatch. If a unit should fail within 180 days

from time of shipment from TechnoVersions, it can be returned for repair or replacement at

TechnoVersions discretion. Products subject to abuse (as determined by TechnoVersions) are

excluded from this limited warranty. TechnoVersions LLC makes no other claims as to suitability and

excludes any liability for direct, indirect or consequential damages. Exclusive remedy is limited to

product replacement or repair. Cost of shipping the product to TechnoVersions is at the customer’s

expense, but the replacement/repaired MeterMatch will be shipped to customer via USPS or UPS

ground at TechnoVersions expense, except for shipments out of the US, in which case

TechnoVersions shipping cost is limited to the cost of domestic shipments. When returning

MeterMatch to TechnoVersions, include a description of the fault to help facilitate repair.

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MeterMatchTM Specifications

Size

1.85"x2.4"x0.93"

Weight

1.2 Oz

Connections

1x6 screw terminal strip

accepting #16-#28 AWG wires

Sender Input

Ohmmeter reading of sender

input to ground

Max current/voltage through

sender 20mA/5Vdc

Resolution approximately 1



for readings less than 100 .

Range 0-3,000



Gauge output

onstant

current sink

Full output range resolution

better than 1%, actual resolution

depends upon working range of

gauge

Input/Output Translation

Meter output current based on

linear interpolation of sender

resistance calibration points.

Four calibration points provided,

minimum of two necessary for

operation.

LED Output

Programmed blinking

Source impedance to anode

400, open-collector to

cathode

Controls

Up, Down, Save buttons

Position rotary switch

(MeterMatch Instruction Manual - Rev 6/2017)