- 5 -
low, and 33
Ω
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, 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. 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
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.
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. 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.