Read all registers at once

When you read the registers one-by-one, which is what the solaredge_mobus
library is doing, you run into the issue where the value and the scale
are sometimes out of sync.

This happens mostly when the values go up or down a lot, like at the
beginning and at the end of the day. At these times the SolarEdge
inverter can change the scale of the values it's returning.

When you read the value register, the scale might be -2, but in the
time between that request, and the request for the scale, the inverter
has changed the scale to -3. So in the next register read, you will get
-3 for the scale, but have a value in the scale of -2. Now when you do
the value calculation, you end up with a factor 10 difference.

So it's better, and also _much_ faster to read out all the registers
at once and then parse the values from this bigger read out.

I'm planning to do a MR back to solaredge_modbus with this change, so
for now i've just included that code into this project.

solaredge_modbus_mqtt.py

@@ -9,6 +9,7 @@ import time
 import paho.mqtt.client as mqtt
 import yaml
 from solaredge_modbus_mqtt import SolarData
+from solaredge_modbus_mqtt import MyInverter
 from pymodbus.exceptions import ConnectionException
 
 if __name__ == '__main__':
@@ -30,7 +31,7 @@ if __name__ == '__main__':
         print('Cannot connect to MQTT on {0}:{1}, error: {2}'.format(config['mqtt']['host'], config['mqtt']['port'], err))
         sys.exit(1)
 
-    inverter = solaredge_modbus.Inverter(
+    inverter = MyInverter(
         host=config['modbus']['host'],
         port=config['modbus']['port'],
         timeout=config['modbus']['timeout'],
@@ -41,7 +42,8 @@ if __name__ == '__main__':
     publishedAutoDiscovery = False
     while run:
         try:
-            solar_data = SolarData(inverter.read_all())
+            raw = inverter.read()
+            solar_data = SolarData(raw)
         except ConnectionException as err:
             print('Cannot connect to SolarEdge Modbus server on {0}:{1}, error: {2}'.format(config['modbus']['host'], config['modbus']['port'], err))
             sys.exit(2)