protected FunctionServiceResult ProcessReadRegisters(Sample[] samples, PacketType? packetType)
{
//Get the raw bytes
var messageBytes = samples
.Select(s => s.Value)
.ToArray();
//We'll assume that this is a response
byte numberOfBytes = messageBytes[2];
//Get the number of registers
var numberOfRegisters = numberOfBytes / 2;
//Get the registers themselves
var registers = GetRegisters(messageBytes, numberOfRegisters, 3);
//Create the visual factory
Func<Visual> visualFactory = () =>
{
var viewModel = new RegistersViewModel(registers);
return new RegistersView()
{
DataContext = viewModel
};
};
var summary = $"{numberOfRegisters} registers.";
return new FunctionServiceResult(summary, visualFactory, packetType);
}
public static FunctionServiceResult Process(Sample[] samples)
{
try
{
IFunctionService service;
if (samples.Length < 5)
{
return new FunctionServiceResult("Packet not long enough.");
}
byte rawFunctionCode = samples[1].Value;
FunctionCode functionCode = (FunctionCode)(rawFunctionCode & 0x7F);
if ((rawFunctionCode & 0x80) > 0)
{
var exceptionDescription = SlaveExceptionDescriptionFactory.GetExceptionDescription(samples[2].Value);
return new FunctionServiceResult(error: exceptionDescription);
}
if (_functionServices.TryGetValue(functionCode, out service))
{
return service.Process(samples);
}
return new FunctionServiceResult(error: "Unsupported function code.");
}
catch (Exception ex)
{
return new FunctionServiceResult(ex.Message);
}
}
public override FunctionServiceResult Process(Sample[] samples)
{
if (samples.Length == NumberOfRegistersMessageLength)
{
return ProcessNumberOfRegisters(samples, PacketType.Request);
}
return ProcessReadRegisters(samples, PacketType.Response);
}
protected FunctionServiceResult ProcessNumberOfRegisters(Sample[] samples, PacketType? packetType)
{
if (samples.Length != NumberOfRegistersMessageLength)
throw new ArgumentException($"The message must be 8 bytes long. It was {samples.Length}.");
//Get the raw bytes
var messageBytes = samples
.Select(s => s.Value)
.ToArray();
ushort address = EndianBitConverter.Big.ToUInt16(messageBytes, 2);
ushort number = EndianBitConverter.Big.ToUInt16(messageBytes, 4);
var summary = $"Read {number} registers starting at {address}";
return new FunctionServiceResult(summary, packetType: packetType);
}
private FunctionServiceResult ProcessWriteRegisters(Sample[] samples)
{
// http://www.simplymodbus.ca/FC16.htm
//Get the raw bytes
var messageBytes = samples
.Select(s => s.Value)
.ToArray();
var dataAddress = EndianBitConverter.Big.ToUInt16(messageBytes, 2);
var numberOfRegisters = EndianBitConverter.Big.ToUInt16(messageBytes, 4);
var bytesToFollow = messageBytes[6];
if (bytesToFollow != numberOfRegisters*2)
{
return
new FunctionServiceResult(
$"The bytes to follow {bytesToFollow} does not match the number of registers {numberOfRegisters}.");
}
var registers = GetRegisters(messageBytes, numberOfRegisters, 7);
Func<Visual> visualFactory = () =>
{
var viewModel = new RegistersViewModel(registers.ToArray(), dataAddress);
return new RegistersView()
{
DataContext = viewModel
};
};
var summary = $"Write {numberOfRegisters} registers starting at register {dataAddress}";
return new FunctionServiceResult(summary, visualFactory, PacketType.Request);
}
public abstract FunctionServiceResult Process(Sample[] samples);
