- 2 -
Theory of Operation
MeterMatch-VR 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-VR, 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 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 end-points.
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.
Note that on some gauges, you may not be able to generate a completely full reading on the gauge,
but you should be able to get close. Empty readings are generally not an issue.
