From 93b33333569b58b426cb06001379d256f5ddb4fe Mon Sep 17 00:00:00 2001
From: Wolfgang Hottgenroth <w.hottgenroth@krohne.com>
Date: Mon, 8 Jul 2019 15:28:46 +0200
Subject: [PATCH] add actual modbus communication

---
 snippets/test8.py             | 12 ------------
 src/CommunicationProcessor.py | 28 ++++++++++++++++++++++++----
 src/Config.py                 |  2 ++
 src/RegisterDatapoint.py      | 23 ++++++++++++++++++++---
 4 files changed, 46 insertions(+), 19 deletions(-)
 delete mode 100644 snippets/test8.py

diff --git a/snippets/test8.py b/snippets/test8.py
deleted file mode 100644
index 4175200..0000000
--- a/snippets/test8.py
+++ /dev/null
@@ -1,12 +0,0 @@
-import queue
-import datetime
-import threading
-import socketserver
-import cmd
-import io
-import paho.mqtt.client as mqtt
-import re
-
-
-
-
diff --git a/src/CommunicationProcessor.py b/src/CommunicationProcessor.py
index ca9492d..c479e87 100644
--- a/src/CommunicationProcessor.py
+++ b/src/CommunicationProcessor.py
@@ -1,5 +1,8 @@
 import threading
 import datetime
+import RS485Ext
+import RegisterDatapoint
+from pymodbus.client.sync import ModbusSerialClient
 
 class CommunicationProcessor(threading.Thread):
     def __init__(self, config, queue):
@@ -8,10 +11,27 @@ class CommunicationProcessor(threading.Thread):
         self.queue = queue
         self.daemon = True
 
+    def __getSerial(self):
+        return RS485Ext.RS485Ext(port=self.config.serialPort, baudrate=self.config.serialBaudRate, stopbits=1,
+                                 timeout=1)
+
+
     def run(self):
+        client = ModbusSerialClient(method='rtu')
+        client.socket = self.getSerial()
+        client.connect()
+
         while True:
             r = self.queue.get()
-            r.process()
-            r.lastContact = datetime.datetime.now()
-            print("Dequeued: {0!s}".format(r))
-            r.enqueued = False
+            try:
+                print("Dequeued: {0!s}".format(r))
+                r.enqueued = False
+                r.process(client)
+            except RegisterDatapoint.DatapointException as e:
+                print("ERROR when processing '{0}': {1!s}".format(r.label, e))
+                if client.socket is None:
+                    print("renew socket")
+                    client.socket = self.getSerial()
+
+
+
diff --git a/src/Config.py b/src/Config.py
index 8278f02..3356973 100644
--- a/src/Config.py
+++ b/src/Config.py
@@ -8,4 +8,6 @@ class Config(object):
         self.cmdAddress = '127.0.0.1'
         self.cmdPort = 9999
         self.registerFile = 'registers.pkl'
+        self.serialPort = '/dev/ttyAMA0'
+        self.serialBaudRate = 9600
 
diff --git a/src/RegisterDatapoint.py b/src/RegisterDatapoint.py
index 0691a83..82dce54 100644
--- a/src/RegisterDatapoint.py
+++ b/src/RegisterDatapoint.py
@@ -1,6 +1,9 @@
 import datetime
+from pymodbus.pdu import ExceptionResponse
+from pymodbus.exceptions import ModbusIOException
 
 
+class DatapointException(Exception): pass
 
 class AbstractModbusDatapoint(object):
     def __init__(self, label, unit, address, count, scanRate):
@@ -19,7 +22,7 @@ class AbstractModbusDatapoint(object):
     def __str__(self):
         return "{0}, {1}: Unit: {2},  Address: {3}, Count: {4}".format(self.type, self.label, self.unit, self.address, self.count)
 
-    def process(self):
+    def process(self, client):
         raise NotImplementedError
 
 
@@ -36,7 +39,7 @@ class HoldingRegisterDatapoint(AbstractModbusDatapoint):
     def __str__(self):
         return "[{0!s}, Read: {1}, Write: {2}, Feedback: {3}".format(super().__str__(), self.publishTopic, self.subscribeTopic, self.feedbackTopic)
 
-    def process(self):
+    def process(self, client):
         successFull = False
         giveUp = False
         if self.writeRequestValue:
@@ -53,6 +56,13 @@ class HoldingRegisterDatapoint(AbstractModbusDatapoint):
         else:
             # perform read operation
             print("Holding register, perform read operation")
+            result = client.read_holding_registers(address=self.address, 
+                                                   count=self.count, 
+                                                   unit=self.unit)
+            if type(result) in [ExceptionResponse, ModbusIOException]:
+                raise DatapointException(result)
+            print("{0}: {1!s}".format(self.label, result.registers))
+
             if successFull:
                 self.lastContact = datetime.datetime.now()
                 # publish value
@@ -79,10 +89,17 @@ class InputRegisterDatapoint(AbstractModbusDatapoint):
     def __str__(self):
         return "[{0!s}, {1}".format(super().__str__(), self.publishTopic)
 
-    def process(self):
+    def process(self, client):
         successFull = False
         giveUp = False
         # perform read operation
+        result = client.read_input_registers(address=self.address,
+                                             count=self.count,
+                                             unit=self.unit)
+        if type(result) in [ExceptionResponse, ModbusIOException]:
+            raise DatapointException(result)
+        print("{0}: {1!s}".format(self.label, result.registers))        
+
         print("Input register, perform read operation")
         if successFull:
             self.lastContact = datetime.datetime.now()