RPICT3V1

This page is for board specific information. More information can be found on the generic page for RPICT series.

• 3 AC current sensor
• 1 AC Voltage sensor.
• Compute RealPower, ApparentPower, PowerFactor, Vrms, Irms.
• Fit on the 2 holes mounting pattern for Raspberrypi.
• Arduino Attiny84 Microcontroller.

Compatibility

Version	Compatible?
Raspberrypi 1 A	Yes
Raspberrypi 1 B	No mounting holes.
Raspberrypi 1 B+	Yes
Raspberrypi 2 B	Yes
Raspberrypi 3 B	Yes
Raspberrypi 3 B+	Yes
Raspberrypi 4 B	Yes
Raspberrypi 5	Yes

• Asus Tinkerboard has been reported to work with RPICT units. Note we wont be able to provide support for the Tinkerboard.

Notice

The RPICT3V1 must have a voltage sensor to compute Real Power. If you do not want to use a voltage sensor and prefer measuring just current then the RPICT3T1 might be more appropriate.

(Note it is possible to use a different sketch (firmware) to make the RPICT3V1 using estimated voltage. However you will have to flash the unit with a special programmer for that.)

Recommended sensors

• AC Current sensor:
  • SCT-013-000
  • SCT-019
  • SCT-006
  • SCT-024 400A/100mA
  • SCT-031 600A/100mA
• AC Voltage sensor:
  • ZMPT101B Module
  • UK: 77DB-06-09
  • EU: 77DE-06-09
  • US: 77DA-10-09

Configuration

Starting from sketch version 1.1 the RPICT3V1 is configured over serial.

See general instructions for configuration below:

Configuration over serial for sketch version 2.0 & 2.1.

Version 2.0 & 2.1 can be configured using the web tool.

Online Config Generator

Default Data Output

If you are running an old version of the firmware click on the link below related to your version.

RPICT3V1 Sketch version 1.3 documentation

Using the default sketch version 2.0 and above the output is

NodeID Realpower1 ApparentPower1 Irms1 Vrms1 PowerFactor1 Realpower2 ApparentPower2 Irms2 Vrms2 PowerFactor2 Realpower3 ApparentPower3 Irms3 Vrms3 PowerFactor3

• RealPower in Watts
• ApparentPower in Watts
• Irms in Amperes (or Estimated Power if Vest different from 1.0)
• Vrms in Volts
• PowerFactor without units.

With sketch version 2.0 & 2.1 and above some channels can be disabled. See this page for more info. RPICT3V1 Disable channels sketch 2

Restore Default Config

You should have received a key when acquiring the unit. Use this key to download and restore the default configuration.
If the key was XXXX then execute these commands below. Replace XXXX with your own key.

$ wget lechacal.com/hardware/c/XXXX.conf
$ lcl-rpict-config.py -w XXXX.conf

View the data with Python

Please note the configuration must have Emonhub format enabled (format=3). The example script below will be a good starting point.

First of all make sure you have python-serial package installed

$ sudo apt-get install python-serial

Then copy the following into an executable file and run it.

This is below for sketch 2.0 and above.

 #!/usr/bin/python3
 import serial
 ser = serial.Serial('/dev/ttyAMA0', 38400)
 
 try:
        while 1:
             # Read one line from the serial buffer
             line = ser.readline().decode().strip()
 
             # Create an array of the data
             Z = line.split(' ')
 
             # Print it nicely
             if len(Z)>15:
                 print ("----------")
                 print ("          \tCT1\tCT2\tCT3") 
                 print ("RealPower:\t%s\t%s\t%s" % (Z[1], Z[6], Z[11]))
                 print ("AppaPower:\t%s\t%s\t%s" % (Z[2], Z[7], Z[12]))
                 print ("Irms     :\t%s\t%s\t%s" % (Z[3], Z[8], Z[13]))
                 print ("Vrms     :\t%s\t%s\t%s" % (Z[4], Z[9], Z[14]))
                 print ("PowerFact:\t%s\t%s\t%s" % (Z[5], Z[10], Z[15]))
 
                        
 except KeyboardInterrupt:
        ser.close()

To get the above example just enter the command below.

wget lechacal.com/RPICT/example/RPICT3V1_DEMO.py.zip
unzip RPICT3V1_DEMO.py.zip

and run it using

python3 RPICT3V1_DEMO.py

Emoncms Config (Emonhub)

For default configuration with sketch version 2.0 and above.

 [[11]]
   nodename = my_RPICT3V1
   hardware = RPICT3V1
   [[[rx]]]
      names = RP1, AP1, Irms1, Vrms1, PF1, RP2, AP2, Irms2, Vrms2, PF2, RP3, AP3, Irms3, Vrms3, PF3
      datacode = 0
      scales = 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
      units = W,W,A,V,.,W,W,A,V,.,W,W,A,V,.

Sketch

Units are sold flashed with sketch for use with a Voltage sensor.

Usage with Voltage sensor

Version 2.0
Version 2.1
Version 2.2 hex→ current default for sold units.

Usage without Voltage sensor

If you wish to use the board without using the voltage sensor use the sketch below. Note power will be estimated power only using fixed voltage setup in configuration.
No Voltage Version 2.0

Once the sketch uploaded write the configuration as follow:

$ wget lechacal.com/RPICT/config/A2/rpict3v1.conf
$ lcl-rpict-config.py -w rpict3v1.conf

Output will be in AMps. Change VEST in config from 1 to 240 or 110 to get estimated power.

CAD Drawing

Related Pages

Howto setup Raspbian for serial read

Gen3_Passive_Component_Setup

How to calibrate the Voltage Port

How to program an Attiny85 or Attiny84

Use Emonhub with RPICT

Flash RPICT Attiny84 with Arduino UNO

FAQ

More generic FAQ are here. Frequently Asked Questions

Why are there 3 Vrms output for only 1 Voltage port?

The RPICT3V1 computes power using associated pairs for Current/Voltage (CV pairs). The result of this computation gives Vrms Irms ActivePower etc. The CV pairs in the RPICT3V1 are
P1-> CT1/V1
P2-> CT2/V1
P3-> CT3/V1

The output reports the result of Vrms for each of these computation. We do expect the three Vrms values to be the nearly the same with a small diffrence because there are computed at a different time.

In practice for voltage monitoring you should just use one of the three Vrms.

However if you need to know precisely which Vrms was used when computing a given Active Power then make sure you compare it against the Vrms it is associated with.