Added main script and config sample

config.json.sample

@@ -0,0 +1,17 @@
+{
+	"port": 5020,
+	"sensors": [
+		{ 
+			"type": "DHT22",
+			"pin": 17,
+			"address_t": 1,
+			"address_h": 3
+		},
+		{ 
+			"type": "DHT22",
+			"pin": 27,
+			"address_t": 5,
+			"address_h": 7
+		}
+	]
+}

read.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+
+import Adafruit_DHT
+import json
+import time
+from collections import defaultdict
+from threading import Thread
+from pymodbus.constants import Endian
+from pymodbus.server.sync import StartTcpServer
+from pymodbus.device import ModbusDeviceIdentification
+from pymodbus.datastore import ModbusSequentialDataBlock
+from pymodbus.datastore import ModbusSlaveContext, ModbusServerContext
+from pymodbus.transaction import ModbusRtuFramer, ModbusAsciiFramer
+from pymodbus.payload import BinaryPayloadBuilder
+import logging
+import logging.handlers as Handlers
+
+logging.basicConfig()
+log = logging.getLogger()
+log.setLevel(logging.DEBUG)
+
+
+file = open('config.json', mode='r')
+config = json.loads(file.read())
+file.close()
+
+def data_update(config, a):
+	context = a[0]
+	while True:
+		for sensor in config['sensors']:
+			# Sensor should be set to Adafruit_DHT.DHT11,
+			# Adafruit_DHT.DHT22, or Adafruit_DHT.AM2302.
+	
+			if sensor['type'] == 'DHT22':
+				sensor_type = Adafruit_DHT.DHT22
+			elif sensor['type'] == 'DHT11':
+				sensor_type = Adafruit_DHT.DHT11
+			elif sensor['type'] == 'AM2302':
+				sensor_type = Adafruit_DHT.AM2302
+			else:
+				raise Exception("Unknown sensor type: " + sensor['type'])
+
+			pin = int(sensor['pin'])
+			humidity, temperature = Adafruit_DHT.read_retry(sensor_type, pin)
+			
+			if humidity is not None and temperature is not None:
+				builder_t = BinaryPayloadBuilder(byteorder=Endian.Big,
+                                   wordorder=Endian.Big)
+				builder_h = BinaryPayloadBuilder(byteorder=Endian.Big,
+                                   wordorder=Endian.Big)
+				builder_t.add_32bit_float(temperature)
+				builder_h.add_32bit_float(humidity)
+				context.setValues(4, int(sensor['address_t']), builder_t.to_registers())
+				context.setValues(4, int(sensor['address_h']), builder_h.to_registers())
+				log.info('Temp={0:0.1f}*C  Humidity={1:0.1f}%'.format(temperature, humidity))
+			else:
+				log.warn('Failed to get reading. Try again!')
+
+store = ModbusSlaveContext(
+        ir=ModbusSequentialDataBlock(0, [17]*100))
+                                
+context = ModbusServerContext(slaves=store, single=True)
+
+thread = Thread(target=data_update, args=(config, context,))
+thread.start()
+    
+StartTcpServer(context, identity=ModbusDeviceIdentification(), address=("0.0.0.0", config['port']))
+