Riden RD6012 - Raw ADC Values and Calibration Procedure

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17. Raw ADC Values and Calibration
The raw ADC values, selectable from the ‘Status info’ setting, can be used to adjust, or confirm, the
calibration settings of the RD60xx.
Vout = ADC(V) * backVoltageScale / 100000 - backVoltageZero
Iout = ADC(I) * backCurrentScale / 100000 - backCurrentZero
For example, let's calibrate the "backVoltage" values:
1) Find ADC(V)
0
, the ADC ‘Zero’ value:
● Ensure the output is OFF and the output capacitors are discharged.
○ Observe the value of ADC(V) for a while.
● Take the highest value and add 1.
(In this example, the highest value observed was: 143.)
○ ADC(V)
0
= 143 + 1 = 144
2) Find ADC(V)
x
, the ADC reading of a known (calibrated) value.
(For this example let it be 50V)
● Set output to 50.00V and turn ON.
● Using the “ENCODER” Knob, adjust output voltage to be as close to 50V, as measured
using a calibrated multimeter.
○ Observe the value of ADC(V) for a while.
● Take the most stable value (usually a middle one).
(In this example, ADC(V)
x
= 29109)
3) Calculate calibration constants:
Scale = (Calibrated Value * 100,000) / (ADC(V)
x
- ADC(V)
0
)
(In this example, ‘Calibrated Value’ = 50V, in tens of mV = 5000)
= (5000 * 100,000) / (29109 - 144)
= 17262
Zero = (ADC(V)
0
* Scale) / 100,000
= (144 * 17262) / 100,000
= 24
Notes:
When calculating with the ADC values for current:
● RD6006 the ‘Calibrated Value’ is in: mA (ie. 1А = 1000)
● RD601x the ‘Calibrated Value’ is in: tens of mA (ie. 1A = 100)