How to calibrate the Voltage Port: Difference between revisions

Revision as of 19:37, 19 November 2016

For board series RPICT7V1, RICT4V3, RPICT3V1 EmonWRT the voltage should be calibrated against the AC/AC adaptor used. We will explain how to calculate this value here.

Equipment needed

Any ac voltage measuring device (multimeter, scope).
AVR programmer
The board to test must be operational.

Steps

Step 1

Upload the sketch where VCAL is a know value. We will use VCAL = 525 in our example.

This can be anything but should be relatively close to the expected final value.

Step 2

Connect the AC/ac adaptor to the board to be tested and note athe reading of the measured voltage. Let's say in our case Vmes = 269.5

Step 3

Use the multimeter to read the real voltage value. In our case Vreal = 245.6

Step 4

Calculate the new VCAL as such

newVCAL = VCAL*Vreal/Vmes

For us here this is newVCAL = 525*245.6/269.5 = 478.44

Step 5

Enter the newVCAL value in the sketch and upload to the MCU.

@@ Line 15: / Line 15: @@
 ===Step 2===
-Connect the AC/ac adaptor and take a reading of the voltage measured. In our case Vmes =  269.5
+Connect the AC/ac adaptor to the board to be tested and note athe reading of the measured voltage. Let's say in our case Vmes =  269.5
 ===Step 3===