yasdidemon.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-

""" A simple demon using the Python wrapper. It searches for SMA inverters and poll the data channels "Pac", "E-Tag", "E-Total" in a loop.
"""

__author__ = "Heiko Prüssing"
__license__ = "MIT License"
__version__ = "0.0.1"
__maintainer__ = "Heiko Prüssing"


# imports

import os
import time
from yasdiwrapper.yasdi import Yasdi, INVALID_HANDLE
from yasdiwrapper.yasdimaster import YasdiMaster, CMD_DEVICE_DETECTION
from yasdiwrapper.sd1channels import CHANNEl_NAME_PAC, CHANNEl_NAME_ETOTAL

# Globals

# Search for YASDI libraries also in the current directory first
os.environ["DYLD_LIBRARY_PATH"] = os.getcwd() # for macOS
os.environ["LD_LIBRARY_PATH"] = os.getcwd() # for Linux/Unix

yasdiMasterLibrary = YasdiMaster()
yasdiLibrary = Yasdi()


# Implementation

class YasdiDemon:

    def pollLiveData(self, devicesList, channelsToRequest, outputFile: str="./data.csv"):
        """Polls for live data on given devices and channel names and put it into a csv file."""

        # The age of the channel value should not older than 1 second
        AGE_OF_VALUE_SECONDS = 1
    
        while True:
            outputBuffer = "ChannelName;ChannelUnit;ValueTimestamp;ChannelValue\n"
            for deviceHandle in devicesList:
                for channelName in channelsToRequest:
                    channelHandle = yasdiMasterLibrary.FindChannelName(deviceHandle, channelName)
                    if INVALID_HANDLE == channelHandle:
                        print(f"Error: Channel {channelName} is missing on device {yasdiMasterLibrary.GetDeviceName(deviceHandle)}. Check your device detection...")
                    else:
                        channelValue = yasdiMasterLibrary.GetChannelValue(channelHandle, deviceHandle, AGE_OF_VALUE_SECONDS)
                        timestamp = yasdiMasterLibrary.GetChannelValueTimeStamp(channelHandle, deviceHandle)
                        channelUnit = yasdiMasterLibrary.GetChannelUnit(channelHandle)
                        # print(f"{channelName};{channelUnit};{timestamp};{channelValue}")
                        outputBuffer = outputBuffer + f"{channelName};{channelUnit};{timestamp};{channelValue}\n"
            
            # Write data to a csv file
            with open(outputFile, 'w', encoding="utf-8") as f:
                f.write(outputBuffer)
                f.close()

            time.sleep(2)

    def start(self):
        try:
            driverHandleList = yasdiLibrary.yasdiGetDrivers()
            if len(driverHandleList) == 0:
                raise Exception("Error: No configured interfaces available! Please check your YASDI configuration try again...")

            # Open all interfaces (drivers)
            for driverHandle in driverHandleList:
                print(f"Open interface driver '{yasdiLibrary.yasdiGetDriverName(driverHandle)}'. Success = {yasdiLibrary.yasdiSetDriverOnline(driverHandle)}" )

            # Search for SMA devices (inverters, etc...)
            print("Start searching SMA devices...")
            COUNT_OF_DEVICES_TO_BE_SEARCHED = 1
            if not yasdiMasterLibrary.DoMasterCmdEx(cmd=CMD_DEVICE_DETECTION, param1=COUNT_OF_DEVICES_TO_BE_SEARCHED):
                print("Device detection failed for some reason. Maybe not all devices are found as requested.")

            # Get the list of found SMA devices
            devicesList = yasdiMasterLibrary.GetDeviceHandles()
            for deviceHandle in devicesList:
                print(f"Found device: {yasdiMasterLibrary.GetDeviceName(deviceHandle)}")

            if len(devicesList) == 0:
                raise Exception("ERROR: No SMA inverters found! Check your hardware or yasdi configuration and try again...")
        
            # Endless poll for live data from devices:
            self.pollLiveData(devicesList, [CHANNEl_NAME_PAC, CHANNEl_NAME_ETOTAL])

        #except Exception as e:
        #    print(f"=> Exception: {e}")

        finally:
            yasdiMasterLibrary.yasdiMasterShutdown()


if __name__ == "__main__":
    yasdiDemon = YasdiDemon()
    yasdiDemon.start()