Quad Current Meter (QCM) Tips

Tips and Tricks

What NOT  to do with the QCM:
Do not use QCM to measure your aircrafts fully amperage load.   There are other devices on the market that will work for that.   The QCM is designed for a single servo on each channel.   Not a battery on channel and plane on the other end. 
Since the QCM is a new product I am sure there will be more for this section later.
Tips and Tricks:
When hooking up your QCM, if at all possible try to isolate the surface you are testing for binding, or are trying to match up.  In other words if you are going to test your Right Aileron, you will want to disconnect all other surfaces from you RX before you plug in your Right Aileron.    All testing should be done this way.  

REASON: Since the sticks on our transmitters do more than one thing, (Throttle/Rudder)-(Elevator/Aileron) it is very easy to bump one surface while trying to test another just in moving the stick around.  When this happens you are causing a voltage jolt (spike/fluctuation) on your RX buss, which in turn will cause a spike to go through the QCM.   This will not hurt the QCM, however it can make it hard to read.  If you are fine with that explanation  skip the next paragraph,,, (I would!)

CAUTION: Calculation Ahead>
If your Servo is drawing 1.1 amps (I ) at a voltage of 8.4 (V ), the wattage will be 9.24 (P ) or ( I x V = P )....  Now lets say you have your whole plane 40% wired up and you are trying to test your Right Aileron, you have a Gang of 4 8711's on your Rudder that you keep bumping.   When you bump that rudder stick you notice that your right Aileron numbers go crazy.   What is happing when you do this is?  You are messen with (V ) which will change the equation, and will show up in elevated Amperage readings.    So in the first equation we figured out that the 8711 was using 9.24 watts (P ) to maintain its position.   When you bump your rudder system you are dropping the Voltage of the buss to 7.6volts (V ).  Now we must work the equation backwards ( P / V = I ) or 9.24(P ) / 7.6(V ) = 1.2(I )  .     As you can see we have gained .1 or 100mA's just from a spike on the buss.  This is why we recommend that you Isolate what you are testing.  
When hooking up your QCM try to land your Servo leads one at a time.   Meaning Start on Servo#1, observe the reading, now plug in Servo#2 etc.   This will allow you to make adjustments as you go along.  You can plug everything in all at once (Let-her Rip Mode), however doing it this way can make it hard to figure out exactly which Servo that is causing the binding.   Remember in a Gang of 4, 1 Servo can cause all the Servos to buzz and draw excessive current.   Eventually you will get thing sorted out doing it this way, however it is not optimal and we suggest you do it one at a time.

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