RPICTlib

Version History

• V1.1.0
  • Frequency Support.
  • ADC Reference can now be set. (Needed for RPICT7V1 Version 4).
  • Various code optimisation.
  • CurrentNode now called SignalNode (We figured out this can equally measure Voltage as well).
• V1.0.1
  • Modified timing control. Now uses better sync checks.
  • Added support for computing Irms alone with PowerNode class. Was missing on previous version.
  • mcp3208 now reading a bit faster. Using full bit banging now.

• V1.0.0
  • Initial version

Usage

Definition and initialisation

Definitions

The library must called in the arduino sketch with the following include.

#include "RPICTlib.h"

Three compiler variable must also be defined.

uint8_t ADC_BITS = 10; 
uint16_t ADC_COUNTS (1 << ADC_BITS);
uint16_t ADC_REF = 3300;   

ADC_BITS is 10 for the RPICT board with attiny84 and 12 for the RPICT with mcp3208.

ADC_REF is either 3300 or 4096 depending on the board type.

Classes

There are fours classes to construct computation nodes. These are

• SignalNode
• PowerNode
• SignalNode_mcp3208
• PowerNode_mcp3208

An example where CT1 is a simple rms compuation node:

SignalNode CT1;

You might take a look into the RPICTlib.h file for more detailed information on these classes.

Initialisation

The begin function is used to initialised the computation node. Usually in the setup section of the Arduino sketch. For example:

CT1.begin(ct1, 83.33);

ct1 being the I/O pin of ct1 and 83.33 the calibration value.

Computation Examples

SignalNode

The SignalNode class is used to compute the RMS value of a signal. It can equally be current or voltage regardless.

Intended for board that uses the ADC of the MCU directly. In particular all RPICT with attiny84 (RPICT3T1, RPICT3V1, RPIZ_CT3T1, RPIZ_CT3V1, RPICT4T4)

calcRMS is the function to call to run the computation.

CT1.calcRMS(N_SAMPLES, sInterval);

where

• N_SAMPLES is the number of samples to collect to compute the RMS signal.
• sInterval is the sampling interval in microseconds. Usual values are 400us for attiny84 and 300us for mcp3208.

See RPICTlib_Example_01.ino for a working example.