Over Serial Configuration - Sketch 2.3

Overview

RPICT board using Atmega microcontrollers can be configured over serial using a utility written in python. This involves boards RPICT7V1 RPICT4V3 version 2 and RPICT8.

Current version allows changes of

• Output format (csv or Emoncms)
• Nodeid (emoncms only)
• Polling (polling interval of data)
• Ical (current calibration value)
• Vcal (Voltage calibration value)
• Vest (estimated voltage for power estimate)

RPICT Configuration tool

The configuration tool can be downloaded directly from the raspberrypi:

$ wget lechacal.com/RPICT/lcl-rpict-config.py.zip
$ unzip lcl-rpict-config.py.zip

Reading current configuration

Using the configurator without option only read the configuration stored in the board.

$ ./lcl-rpict-config.py

This yields

# RPICT Configuration Utility
# Read only
# Now reset RPICT hardware

Once the board has received the reset the configuration will be shown. How to reset the board

# 
# Configuration in memory:
# 
# Structure: 0xa0
# Format: 0
# NodeId: 11
# Polling: 5000
# ICAL: 83.330002
# VCAL: 560.000000
# VEST: 240.000000
#

Note. Every time the configuration is read from the board it stores a config file in /tmp/rpict.config.

Modify the configuration

To change the values the configurator must be fed with a file containing the new values. We will use the example of a RPICT7V1. Such file looks as below.

[main]
format = 0
nodeid = 11
polling = 5000
kcal = 545.0 83.33 83.33 83.33 83.33 83.33 83.33 83.33
vest = 0
Nnode = 7
Nchan = 15
HWSCT = 8 7 6 5 4 3 2 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
HWMCPSCT = 10 10 10 10 10 10 10 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
HWVOL = 1 1 1 1 1 1 1 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
HWMCPVOL = 10 10 10 10 10 10 10 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
CHTYPE = 1 1 1 1 1 1 1 4 4 4 4 4 4 4 3 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
CHID = 0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255

We save this file in rpict7v1.conf. Then we can now start the configurator with the -w option.

$ ./lcl-rpict-config.py -w rpict7v1.conf

Once reset the configurator will read the old config then write the new config and display the newly stored one again.

# RPICT Configuration Utility
# Configuration will be overwritten (Ctrl C to cancel)
# Now reset RPICT hardware
# 
# Configuration in memory:
# 
# Structure: 0xa0
# Format: 0
# NodeId: 10
# Polling: 5000
# ICAL: 83.330002
# VCAL: 545.000000
# VEST: 240.000000
# 
# Writing configuration with file rpict3t1.conf
# 
# Configuration in memory:
# 
# Structure: 0xa0
# Format: 1
# NodeId: 11
# Polling: 5000
# ICAL: 83.330002
# VCAL: 560.000000
# VEST: 240.000000
#

The configuration file

The configuration file fed into the utlity must have the format below:

[main]
format = 0
nodeid = 11
polling = 5000
kcal = 545.0 83.33 83.33 83.33 83.33 83.33 83.33 83.33
vest = 0
Nnode = 7
Nchan = 15
HWSCT = 8 7 6 5 4 3 2 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
HWMCPSCT = 10 10 10 10 10 10 10 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
HWVOL = 1 1 1 1 1 1 1 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
HWMCPVOL = 10 10 10 10 10 10 10 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
CHTYPE = 1 1 1 1 1 1 1 4 4 4 4 4 4 4 3 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
CHID = 0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255

format indicate which format output will be used. Must be an integer number.
0 - CSV
1 - Emoncms
2 - Emoncms as float (must have datatype f setup in emonhub config)

nodeid Only used in emoncms format. Will set the node id.

polling Number of milliseconds between each data to be sent to the raspberrypi.

kcal Current or Volatge calibration coefficient.

vest Voltage to compute estimated power. Usually 240V or 110V. Must be present even is not used. Set vest=1 to obtain output as ampere instead of watts. Set vest=1000 to get milliampere.

Nnode Number of combination node to compute.

Nchan Number of channels (or fields) to output.

HWSCT Pin configuration of a current input.

HWMCPSCT Master or slave identifier for current input.

HWVOL Pin configuration of a voltage input.

HWMCPVOL Master or slave identifier for voltage input.

Combination nodes

Combination nodes are small programs in the microcontroller that computes power given a current/voltage couple.

Four given parameters must be provided. They are the pin numbers where to find the current and voltage and also which slave (or master) is to be used.

For example if

HWSCT = 8 
HWMCPSCT = 6 
HWVOL = 1 
HWMCPVOL = 10

will use current ct1 (8) on slave 1 (6) computed against voltage1 (1) on master board (10).

The tables below gives all pin assignment:

current_pin voltage_pin

Pin number	RPICT7V1	RPICT8	RPICT4V3
1	V1	CT8	V3
2	CT7	CT7	V2
3	CT6	CT6	V1
4	CT5	CT5	nc
5	CT4	CT4	CT4
6	CT3	CT3	CT3
7	CT2	CT2	CT2
8	CT1	CT1	CT1

slave master pins

Pin number	Board type
10	Master
6	Slave 1
7	Slave 2
8	Slave 3
9	Slave 4

Channels

We are refering as a channel here a data stream to be sent out. For example Vrms and Realpower derived from a same sensor will be two different channels.

These are configured with two numbers. The first one is the combination id defined above. Note the first combination id is zero (0). The second number identifies the type of channel. For example:

CHTYPE = 3 
CHID = 0

Uses voltage/current combination node id 0. Channel type 3 which is Vrms (as the table below describes).

The table below shows the convention being used:

code	Channel Type	Description
0	None
1	Real Power	Real Power in Watts
2	Apparent Power	Apparent Power in Watts. This is Irms*Vrms
3	Vrms	Rms Voltage in Volts
4	Irms	Rms current in milliAmps
5	Estimated Power	Estimated Power in Watts. This is Irms*Vest.

How to reset the board

Use a small jumper to link the reset pin with the ground. This can be found on the 3x2 6 pin ISP connector.

Make contact with the two pins then remove the jumper. This will reset the board.