From 2460f570d8e1b00fd0450e4f0cd20416848b9d0a Mon Sep 17 00:00:00 2001
From: Wolfgang Hottgenroth <w.hottgenroth@krohne.com>
Date: Wed, 17 Jul 2019 14:49:01 +0200
Subject: [PATCH] another converter

---
 src/Converters.py        |  7 +++++++
 src/RegisterDatapoint.py | 24 +++++++++++++++++++++---
 src/registers.json       |  4 ++++
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/Converters.py b/src/Converters.py
index a79af12..8870fc6 100644
--- a/src/Converters.py
+++ b/src/Converters.py
@@ -3,9 +3,16 @@
 # out: from MQTT to Modbus, input is the format received from MQTT, output shall be a list of 
 #      16bit integers to be written to the Modbus slave
 
+import struct
+
+
 Converters = {
     "dht20TOFloat": {
         "in": lambda x : float(x[0]) / 10.0,
         "out": None
+    },
+    "uint32": {
+        "in": lambda x : struct.unpack('I', x)[0],
+        "out": lambda x : struct.pack('I', x)
     }
 }
\ No newline at end of file
diff --git a/src/RegisterDatapoint.py b/src/RegisterDatapoint.py
index e13e2c7..b12d8c8 100644
--- a/src/RegisterDatapoint.py
+++ b/src/RegisterDatapoint.py
@@ -71,10 +71,19 @@ class HoldingRegisterDatapoint(AbstractModbusDatapoint):
             # perform write operation
             logger.debug("Holding register, perform write operation")
             self.processCount += 1
-            v = int(self.writeRequestValue)
+            values = None
+            logger.debug("{0}: raw: {1!s}".format(self.label, self.writeRequestValue))
+            if self.converter and Converters.Converters[self.converter]['out']:
+                try:
+                    values = Converters.Converters[self.converter]['out'](self.writeRequestValue)
+                    logger.debug("{0}: converted: {1!s}".format(self.label, values))
+                except Exception as e:
+                    raise DatapointException("Exception caught when trying to converter modbus data: {0!s}".format(e))
+            else:
+                values = [int(self.writeRequestValue)]
             result = client.write_registers(address=self.address,
                                            unit=self.unit,
-                                           values=[v])
+                                           values=values)
             logger.debug("Write result: {0!s}".format(result))                
             self.writeRequestValue = None
         else:
@@ -88,7 +97,16 @@ class HoldingRegisterDatapoint(AbstractModbusDatapoint):
                 self.errorCount += 1
                 raise DatapointException(result)
             logger.debug("{0}: {1!s}".format(self.label, result.registers))
-            pubQueue.put(MqttProcessor.PublishItem(self.publishTopic, str(result.registers)))
+            value = None
+            if self.converter and Converters.Converters[self.converter]['in']:
+                try:
+                    value = Converters.Converters[self.converter]['in'](result.registers)
+                    logger.debug("{0}: converted: {1!s}".format(self.label, value))
+                except Exception as e:
+                    raise DatapointException("Exception caught when trying to converter modbus data: {0!s}".format(e))
+            else:
+                value = result.registers
+            pubQueue.put(MqttProcessor.PublishItem(self.publishTopic, str(value)))
             self.lastContact = datetime.datetime.now()
     
     def onMessage(self, value):
diff --git a/src/registers.json b/src/registers.json
index 9de77d6..2016041 100644
--- a/src/registers.json
+++ b/src/registers.json
@@ -43,6 +43,7 @@
             "count": 2,
             "feedbackTopic": null,
             "label": "Counter1",
+            "converter": "uint32",
             "publishTopic": "Pub/Counter1",
             "scanRate": null,
             "subscribeTopic": null,
@@ -56,6 +57,7 @@
             "count": 2,
             "feedbackTopic": null,
             "label": "Counter2",
+            "converter": "uint32",
             "publishTopic": "Pub/Counter2",
             "scanRate": null,
             "subscribeTopic": null,
@@ -69,6 +71,7 @@
             "count": 2,
             "feedbackTopic": null,
             "label": "Counter3",
+            "converter": "uint32",
             "publishTopic": "Pub/Counter3",
             "scanRate": null,
             "subscribeTopic": null,
@@ -82,6 +85,7 @@
             "count": 2,
             "feedbackTopic": null,
             "label": "Counter4",
+            "converter": "uint32",
             "publishTopic": "Pub/Counter4",
             "scanRate": 1.0,
             "subscribeTopic": null,