In this article the message handling is being improved and a Dimmer is added to the device classes.

The article is building upon a number of other articles previously published on this site. It is highly recommended to read those before proceeding.

• An introduction to Z-Wave programming in C#
• An introduction to the Z-Wave protocol
• The Z-Wave protocol in C# – Part 1
• The Z-Wave protocol in C# – Part 2

A message sequence has to be terminated before a new one can be initiated – in order to comply with the specifications. The current strategy is relying on the device object to determine when a message sequence is completed and to send a notification.
In the previous article only one device was being used and the message sequence for switching on node ‘6′ was looking like the below sequence.

/*
    Message sent: 01 09 00 13 06 03 20 01 FF 05 3B
    Message received: 06
    Message received: 01 04 01 13 01 E8
    Message sent: 06
*/

All the messages coming from the Z-Wave controller were intented for only that specific device object. In this article multiple devices are in play and this adds a complexity in terms of identifying the owner of the messages from the Z-Wave controller. All the device objects will signal ‘message completed’ if they can’t distinguish between messages that they are suppose to react to and those that are not relevant. Remember that all incoming messages are passed on to all the device objects.
The Z-Wave protocol specifies something called a callback id. It can be used to keep track of request/response pairs. A callback id is being defined every time a device object sends a request. » Read more: The Z-Wave protocol in C# – Part 3

In the previous article the client had to control the timing of the message sending. This responsibility is now moved away from the client. A new set of classes are introduced to represent the Z-Wave devices that the client is communicating with.

The functionality of the implementation remains the same as for the previous article. The Z-Wave device is switched off and then on.

Switch s = new Switch(nodeId, zwavePort)
s.Off();
s.On();

It is important to understand the previous articles to get the most out of this example.

• An introduction to Z-Wave programming in C#
• An introduction to the Z-Wave protocol
• The Z-Wave protocol in C# – Part 1

The same devices and configurations are used as in ‘The Z-Wave protocol in C#‘.

The Switch class is responsible for building the messages for switching the Z-Wave device on and off and handling the incoming messages from the Z-Wave controller.

class Switch : ZWaveNode
{
    public void On()
    {
        ...
    }
 
    public void Off()
    {
        ...
    }
 
    public void MessageHandler(byte[] message)
    {
        ...
    }
}

» Read more: The Z-Wave protocol in C# – Part 2

The example developed in this article will be able to switch on a Z-Wave device and the switch it off again. This requires some of the basic Z-Wave protocol elements to be implemented.

It is important to understand the two previous articles to get the most out of the example shown here.

• An introduction to Z-Wave programming in C#
• An introduction to the Z-Wave protocol

For this example the same devices and configurations are used as in ‘An introduction to Z-Wave programming in C#

‘.
The ZWavePort class will be responsible for the basic communication and protocol handling.

class ZWavePort
{
    ...
}

» Read more: The Z-Wave protocol in C# – Part 1

In the first article about Z-Wave programming in C# the program was able to either switch on or switch off a Z-Wave device. In this article some of the basic principles of the Z-Wave protocol will be explored. This will provide the basic understanding for a modification to the code that will be done in a later article. With the modification to the code it will be able to switch the device on and then switch it off . This does not sound like much but it requires the C# program to follow the Z-Wave protocol.

The Z-Wave protocol is based on the following principle.

» Read more: An introduction to the Z-Wave protocol