PyPCC

Python OPC-UA server to control the I2C devices in the LTS.

• opcuserv.py: OPC-UA server that expose (visible) variables and methods.

Prerequisites

Requirements

This Python3 code uses other Python3 modules:

• opcua
• pyyaml
• numpy

We recommend to install a virtual environment and then install the dependencies there. For convenience we have added the relevant modules to the file requirements.txt that can be used to install them with pip3: python3 -m pip install -r requirements.txt

Below are step-by-step instructions that show how to install the dependencies neatly in a Python3 virtual environment.

# Create a Python3 virtual environment with the name "env"
python3 -m venv env
# Activate the virtual environment
. env/bin/activate
# Update the already installed modules in the virtual environment since they are usually outdated
python3 -m pip install --upgrade pip wheel
# Deactivate the virtual environment and start it again
deactivate
. env/bin/activate
# And finally install the module dependencies
python3 -m pip install -r requirements.txt

Execute it

The software can be simply executed with Python3: python3 opcuaserv.py

Optional parameters are explained when the -h or --help parameter is supplied:

python3 opcuaserv.py --help
cryptography is not installed, use of crypto disabled
cryptography is not installed, use of crypto disabled
usage: opcuaserv.py [-h] [-s] [--no-lib-hack] [-p PORT]

optional arguments:
  -h, --help            show this help message and exit
  -s, --simulator       Do not connect to I2c, but simulate behaviour.
  --no-lib-hack         Do not require a hacked opcua library. Breaks behaviour.
  -p PORT, --port PORT  Port number to listen on [4842].

LTS structure

Raspberry pi (LTS_pypcc.yaml -> I2C controller on raspberry pi)

Control PCB (LTS_switch.yaml -> I2C switch)

RCU2 PCB (LTS_RCUx.yaml -> I2C devices)

RCU2 Dither source (LTS_RCU2_dither.yaml -> I2C bitbang)

ADC (LTS_RCU2_ADC.yaml -> SPI bitbang2)

Clock PCB (LTS_clk.yaml -> I2C device)

PLL (LTS_clkPLL.yaml -> SPI bitbang1)