Hello,
I’m trying to determine if it’s possible to calculate the cost of kilowatt-hours consumed during off-peak hours (€0.1672/KWh) and peak hours (€0.2285/KWh) based on the time period (for example, peak hours from 07:30 to 23:30 with a rate of €0.2285/KWh), and the same for off-peak hours. Currently, watt-hours are recorded in the InfluxDB database without being calculated based on hours, which prevents me from defining two separate calculations in Grafana. I would like to know what would be the best way to achieve this, please.
I had opened a topic on the Grafana community, but it seems that Grafana cannot perform this calculation, to the best of my knowledge: https://community.grafana.com/t/calculation-of-consumption-over-a-period-and-then-converting-it-into-currency/103411
Therefore, I’m wondering whether it would be better to work on the InfluxDB side or if I should make modifications on the Python side. I’m not quite sure how I could do this in the simplest and least risky way in terms of future server updates.
I hope I’ve provided enough details for you to assist me.
Thank you very much for your help.
Grafana version and operating system used :
Grafana v10.1.1 (0cfa76b22d) on Ubuntu 18.04
The database I’m using is InfluxDB :
InfluxDB v1.7.6 (git: 1.7 01c8dd416270f424ab0c40f9291e269ac6921964)
Chronograf Version: 1.7.11
Grafana v10.1.1 (0cfa76b22d)
I plan to upgrade InfluxDB to version 2 or 3, so if it’s necessary to do so, please let me know.
My current Python function in the script is:
def get_args():
#Parse command line arguments.
parser = argparse.ArgumentParser(description='Read data from PZEM-004t and send it to InfluxDB.')
parser.add_argument('-db', '--database', type=str, help='Database name', required=True)
parser.add_argument('-sn', '--session', type=str, help='Session', required=True)
parser.add_argument('-rn', '--run', type=str, help='Hostname or Number', required=False, default=datetime.datetime.now().strftime("%Y%m%d%H%M"))
args = parser.parse_args()
dbname = args.database
runNo = args.run
session = args.session
return dbname, session, runNo
def get_sensor_data():
#Read data from PZEM-004t sensor.
## CODE PYTHON ##
master = modbus_rtu.RtuMaster(serial_port)
master.set_timeout(2.0)
master.set_verbose(True)
data = master.execute(1, cst.READ_INPUT_REGISTERS, 0, 10)
voltage = data[0] / 10.0
current = (data[1] + (data[2] << 16)) / 1000.0
power = (data[3] + (data[4] << 16)) / 10.0
energy = data[5] + (data[6] << 16)
frequency = data[7] / 10.0
powerFactor = data[8] / 100.0
alarm = data[9]
# Changing power alarm value to 100 W
# master.execute(1, cst.WRITE_SINGLE_REGISTER, 1, output_value=100)
master.close()
serial_port.close()
return {
"Voltage [V]": voltage,
"Current [A]": current,
"Power [W]": power,
"Energy [Wh]": energy,
"Frequency [Hz]": frequency,
"Power factor []": powerFactor,
"Alarm": alarm
}
except Exception as e:
print(f"An error occurred: {str(e)}")
logging.error(f"An error occurred: {str(e)}")
return None
def send_data_to_influxdb(dbname, runNo, data):
#Send data to InfluxDB.
if data is not None:
now = datetime.datetime.utcnow().isoformat()
datapoints = [
{
"measurement": "watts",
"tags": {
"host": runNo,
},
"time": now,
"fields": data
}
]
client = InfluxDBClient(HOST, PORT, USER, PASSWORD, dbname)
try:
result = client.write_points(datapoints)
if result:
logging.info("Data sent to InfluxDB successfully.")
print("Data sent to InfluxDB successfully.")
else:
logging.error("Failed to send data to InfluxDB.")
print("Failed to send data to InfluxDB.")
except Exception as e:
logging.error(f"An error occurred while sending data to InfluxDB: {str(e)}")
print(f"An error occurred while sending data to InfluxDB: {str(e)}")
if __name__ == "__main__":
dbname, session, runNo = get_args()
try:
while True:
sensor_data = get_sensor_data()
send_data_to_influxdb(dbname, runNo, sensor_data)
time.sleep(SAMPLING_PERIOD)
except KeyboardInterrupt:
logging.error("Program stopped by keyboard interrupt [CTRL_C] by user.")
print("Program stopped by keyboard interrupt [CTRL_C] by user.")
finally:
logging.shutdown()
