[Modbus] 如何 用 C# 開發 Modbus Master Protocol - (12) 實作 AsciiModbusRequest
續上篇，接下來，來實作做後一個模型Modbus ASCII Request
如下圖紅框：
下圖為 ASCII 框架
以下是我實作LRC演算法的心得：
- Start 符號為":"
- End符號為"\r\n"
- LRC 在計算時不包含 Start 和 End 符號
- 計算過程中，先用 byte[] 取得 LRC byte[]，再把整個 byte[] 轉成 Hex，再轉成 ASCII byte[]，最後再加上 Start 和 End，整個過程花費了我相當多的時間。
如下段程式碼
{
var lrc = ModbusUtility.CalculateLRC(OriginalArray);
var pdu = ModbusUtility.BytesToHexString(OriginalArray);
var adu = Encoding.ASCII.GetBytes(ModbusUtility.ASCII_START_SYMBOL + pdu + lrc + ModbusUtility.ASCII_END_SYMBOL);
return adu;
}
完整程式碼如下：
{
public override byte[] ReadCoils(byte Unit, ushort StartAddress, ushort Quantity)
{
this.QuantityValidate(StartAddress, Quantity, 1, 2000);
var requestArray = this.createReadMessage(Unit, EnumModbusFunctionCode.ReadCoils, StartAddress, Quantity);
return requestArray;
}
public override byte[] ReadDiscreteInputs(byte Unit, ushort StartAddress, ushort Quantity)
{
this.QuantityValidate(StartAddress, Quantity, 1, 2000);
var requestArray = this.createReadMessage(Unit, EnumModbusFunctionCode.ReadDiscreteInputs, StartAddress, Quantity);
return requestArray;
}
public override byte[] ReadHoldingRegisters(byte Unit, ushort StartAddress, ushort Quantity)
{
this.QuantityValidate(StartAddress, Quantity, 1, 175);
var requestArray = this.createReadMessage(Unit, EnumModbusFunctionCode.ReadHoldingRegisters, StartAddress, Quantity);
return requestArray;
}
public override byte[] ReadInputRegisters(byte Unit, ushort StartAddress, ushort Quantity)
{
this.QuantityValidate(StartAddress, Quantity, 1, 175);
var requestArray = this.createReadMessage(Unit, EnumModbusFunctionCode.ReadInputRegisters, StartAddress, Quantity);
return requestArray;
}
public override byte[] WriteSingleCoil(byte Unit, ushort OutputAddress, bool OutputValue)
{
ushort outputValue = 0x0000;
if (OutputValue)
{
outputValue = 0xFF00;
}
using (MemoryStream memory = new MemoryStream())
{
memory.WriteByte(Unit);
memory.WriteByte((byte)EnumModbusFunctionCode.WriteSingleCoil);
memory.WriteByte((byte)(OutputAddress >> 8));
memory.WriteByte((byte)OutputAddress);
memory.WriteByte((byte)(outputValue >> 8));
memory.WriteByte((byte)(outputValue));
var aduArray = toAsciiData(memory.ToArray());
return aduArray;
}
}
public override byte[] WriteSingleRegister(byte Unit, ushort OutputAddress, short OutputValue)
{
using (MemoryStream memory = new MemoryStream())
{
memory.WriteByte((byte)Unit);
memory.WriteByte((byte)EnumModbusFunctionCode.WriteSingleRegister);
memory.WriteByte((byte)(OutputAddress >> 8));
memory.WriteByte((byte)(OutputAddress));
memory.WriteByte((byte)(OutputValue >> 8));
memory.WriteByte((byte)(OutputValue));
var aduArray = toAsciiData(memory.ToArray());
return aduArray;
}
}
public override byte[] WriteMultipleCoils(byte Unit, ushort StartAddress, ushort Quantity, byte[] OutputValues)
{
this.QuantityValidate(StartAddress, Quantity, 1, 0x07B0);
byte counter = base.GetByteCount(Quantity);
using (MemoryStream memory = new MemoryStream())
{
memory.WriteByte((byte)Unit);
memory.WriteByte((byte)EnumModbusFunctionCode.WriteMultipleCoils);
memory.WriteByte((byte)(StartAddress >> 8));
memory.WriteByte((byte)(StartAddress));
memory.WriteByte((byte)(Quantity >> 8));
memory.WriteByte((byte)(Quantity));
memory.WriteByte((byte)(counter));
memory.Write(OutputValues, 0, OutputValues.Length);
var lrc = ModbusUtility.CalculateLRC(memory.ToArray());
var pdu = ModbusUtility.BytesToHexString(memory.ToArray());
var adu = Encoding.ASCII.GetBytes(ModbusUtility.ASCII_START_SYMBOL + pdu + lrc + ModbusUtility.ASCII_END_SYMBOL);
return adu;
}
}
public override byte[] WriteMultipleRegisters(byte Unit, ushort StartAddress, ushort Quantity, short[] OutputValues)
{
this.QuantityValidate(StartAddress, Quantity, 1, 0x007B);
var outputArray = base.GetByteCount(OutputValues);
byte counter = (byte)outputArray.Length;
if (Quantity * 2 != outputArray.Length)
{
ModbusException.GetModbusException(0x02);
}
using (MemoryStream memory = new MemoryStream())
{
memory.WriteByte((byte)Unit);
memory.WriteByte((byte)EnumModbusFunctionCode.WriteMultipleRegisters);
memory.WriteByte((byte)(StartAddress >> 8));
memory.WriteByte((byte)(StartAddress));
memory.WriteByte((byte)(Quantity >> 8));
memory.WriteByte((byte)(Quantity));
memory.WriteByte((byte)(counter));
memory.Write(outputArray, 0, outputArray.Length);
var aduArray = toAsciiData(memory.ToArray());
return aduArray;
}
}
private byte[] createReadMessage(byte Unit, EnumModbusFunctionCode FunctionCode, ushort StartAddress, ushort Quantity)
{
using (MemoryStream memory = new MemoryStream())
{
memory.WriteByte(Unit);
memory.WriteByte((byte)FunctionCode);
memory.WriteByte((byte)(StartAddress >> 8));
memory.WriteByte((byte)StartAddress);
memory.WriteByte((byte)(Quantity >> 8));
memory.WriteByte((byte)(Quantity));
var aduArray = toAsciiData(memory.ToArray());
return aduArray;
}
}
private byte[] toAsciiData(byte[] OriginalArray)
{
var lrc = ModbusUtility.CalculateLRC(OriginalArray);
var pdu = ModbusUtility.BytesToHexString(OriginalArray);
var adu = Encoding.ASCII.GetBytes(ModbusUtility.ASCII_START_SYMBOL + pdu + lrc + ModbusUtility.ASCII_END_SYMBOL);
return adu;
}
}
建立單元測試，同樣的期望資料仍是藉由工具取得。
[TestMethod()]
public void ReadCoilsTest()
{
AsciiModbusRequest target = new AsciiModbusRequest();
byte Unit = 1;
ushort StartAddress = 0;
ushort Quantity = 10;
byte[] expected = _modbusUtility.HexStringToBytes("3A 30 31 30 31 30 30 30 30 30 30 30 41 46 34 0D 0A");
byte[] actual;
actual = target.ReadCoils(Unit, StartAddress, Quantity);
Assert.IsTrue(expected.SequenceEqual(actual));
}
[TestMethod()]
public void ReadDiscreteInputsTest()
{
AsciiModbusRequest target = new AsciiModbusRequest();
byte Unit = 1;
ushort StartAddress = 0;
ushort Quantity = 10;
byte[] expected = _modbusUtility.HexStringToBytes("3A 30 31 30 32 30 30 30 30 30 30 30 41 46 33 0D 0A");
byte[] actual;
actual = target.ReadDiscreteInputs(Unit, StartAddress, Quantity);
Assert.IsTrue(expected.SequenceEqual(actual));
}
[TestMethod()]
public void ReadHoldingRegistersTest()
{
AsciiModbusRequest target = new AsciiModbusRequest();
byte Unit = 1;
ushort StartAddress = 0;
ushort Quantity = 10;
byte[] expected = _modbusUtility.HexStringToBytes("3A 30 31 30 33 30 30 30 30 30 30 30 41 46 32 0D 0A");
byte[] actual;
actual = target.ReadHoldingRegisters(Unit, StartAddress, Quantity);
Assert.IsTrue(expected.SequenceEqual(actual));
}
[TestMethod()]
public void ReadInputRegistersTest()
{
AsciiModbusRequest target = new AsciiModbusRequest();
byte Unit = 1;
ushort StartAddress = 0;
ushort Quantity = 10;
byte[] expected = _modbusUtility.HexStringToBytes("3A 30 31 30 34 30 30 30 30 30 30 30 41 46 31 0D 0A");
byte[] actual;
actual = target.ReadInputRegisters(Unit, StartAddress, Quantity);
Assert.IsTrue(expected.SequenceEqual(actual));
}
[TestMethod()]
public void WriteSingleCoilTest()
{
AsciiModbusRequest target = new AsciiModbusRequest();
byte Unit = 1;
ushort OutputAddress = 1;
bool OutputValue = true;
byte[] expected = _modbusUtility.HexStringToBytes("3A 30 31 30 35 30 30 30 31 46 46 30 30 46 41 0D 0A");
byte[] actual;
actual = target.WriteSingleCoil(Unit, OutputAddress, OutputValue);
Assert.IsTrue(expected.SequenceEqual(actual));
}
[TestMethod()]
public void WriteSingleRegisterTest()
{
AsciiModbusRequest target = new AsciiModbusRequest();
byte Unit = 1;
ushort OutputAddress = 2;
short OutputValue = 123;
byte[] expected = _modbusUtility.HexStringToBytes("3A 30 31 30 36 30 30 30 32 30 30 37 42 37 43 0D 0A");
byte[] actual;
actual = target.WriteSingleRegister(Unit, OutputAddress, OutputValue);
Assert.IsTrue(expected.SequenceEqual(actual));
}
[TestMethod()]
public void WriteMultipleCoilsTest()
{
AsciiModbusRequest target = new AsciiModbusRequest();
ModbusUtility ModbusUtility = new ModbusUtility();
byte Unit = 1;
ushort StartAddress = 0;
ushort Quantity = 3;
byte[] OutputValues = new byte[] { 3 };
byte[] expected = ModbusUtility.HexStringToBytes("3A 30 31 30 46 30 30 30 30 30 30 30 33 30 31 30 33 45 39 0D 0A");
byte[] actual;
actual = target.WriteMultipleCoils(Unit, StartAddress, Quantity, OutputValues);
Assert.IsTrue(expected.SequenceEqual(actual));
}
[TestMethod()]
public void WriteMultipleRegistersTest()
{
AsciiModbusRequest target = new AsciiModbusRequest();
byte Unit = 1;
ushort StartAddress = 0;
ushort Quantity = 24;
short[] OutputValues = new short[] { 12, 0, 0, 987, -98, 1, 456, 0, 123, -8, 0, 0, 0, 234, 112, 0, 3458, -89, 0, 0, 0, 988, 0, 0 };
byte[] expected = _modbusUtility.HexStringToBytes("3A 30 31 31 30 30 30 30 30 30 30 31 38 33 30 30 30 30 43 30 30 30 30 30 30 30 30 30 33 44 42 46 46 39 45 30 30 30 31 30 31 43 38 30 30 30 30 30 30 37 42 46 46 46 38 30 30 30 30 30 30 30 30 30 30 30 30 30 30 45 41 30 30 37 30 30 30 30 30 30 44 38 32 46 46 41 37 30 30 30 30 30 30 30 30 30 30 30 30 30 33 44 43 30 30 30 30 30 30 30 30 37 36 0D 0A");
byte[] actual;
actual = target.WriteMultipleRegisters(Unit, StartAddress, Quantity, OutputValues);
Assert.IsTrue(expected.SequenceEqual(actual));
}
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Microsoft MVP Award 2010~2017 C# 第四季
Microsoft MVP Award 2018~2022 .NET
