1.4.5 PelcoD类

PelcoD类主要封装了控制云台的Pelco-D协议，该协议由7个字节构成。第1个字节为同步字节，始终为FFH；第2个字节为地址码，也就是摄像头的逻辑地址号；第3、4个字节表示指令码，即执行哪项操作；第5、6个字节表示数据码，用于指定摄像头的水平、垂直方向移动速度；第7个字节为校验码。PelcoD类中通过将Pelco-D协议中的7个字节返回为串口消息值来对云台进行控制，其关键代码如下：

例程10 代码位置：光盘\TM\01\VWMS\VWMS\CommonClass\PelcoD.cs

private string watchdir = ""; //监控方向

private static readonly byte STX = 0xFF; //同步字节

#region 监控方向和定时监控实体

public string WatchDir

{

get

{

return watchdir;

}

set

{

watchdir = value;

}

}

#endregion

#region 基本指令定义

#region 指令码

private const byte FocusNear = 0x01; //增加聚焦

private const byte IrisOpen = 0x02; //减小光圈

private const byte IrisClose = 0x04; //增加光圈

private const byte CameraOnOff = 0x08; //摄像机打开和关闭

private const byte AutoManualScan = 0x10; //自动和手动扫描

private const byte Sense = 0x80; //Sense码

#endregion

#region 指令码

private const byte PanRight = 0x02; //右

private const byte PanLeft = 0x04; //左

private const byte TiltUp = 0x08; //上

private const byte TiltDown = 0x10; //下

private const byte ZoomTele = 0x20; //增加对焦

private const byte ZoomWide = 0x40; //减小对焦

private const byte FocusFar = 0x80; //减小聚焦

#endregion

#region 镜头左右平移的速度

private const byte PanSpeedMin = 0x00; //停止

private const byte PanSpeedMax = 0xFF; //最高速

#endregion

#region 镜头上下移动的速度

private const byte TiltSpeedMin = 0x00; //停止

private const byte TiltSpeedMax = 0x3F; //最高速

#endregion

#endregion

#region 云台控制枚举

public enum Switch { On = 0x01, Off = 0x02 } //雨刷控制

public enum Focus { Near = FocusNear, Far = FocusFar } //聚焦控制

public enum Zoom { Wide = ZoomWide, Tele = ZoomTele } //对焦控制

public enum Tilt { Up = TiltUp, Down = TiltDown } //上下控制

public enum Pan { Left = PanLeft, Right = PanRight } //左右控制

public enum Scan { Auto, Manual } //自动和手动控制

public enum Iris { Open = IrisOpen, Close = IrisClose } //光圈控制

#endregion

#region 云台控制方法

//雨刷控制

public byte[] CameraSwitch(uint deviceAddress, Switch action)

{

byte m_action = CameraOnOff;

if (action == Switch.On)

m_action = CameraOnOff + Sense;

return Message.GetMessage(deviceAddress, m_action, 0x00, 0x00, 0x00);

}

//光圈控制

public byte[] CameraIrisSwitch(uint deviceAddress, Iris action)

{

return Message.GetMessage(deviceAddress, (byte)action, 0x00, 0x00, 0x00);

}

//聚焦控制

public byte[] CameraFocus(uint deviceAddress, Focus action)

{

if (action == Focus.Near)

return Message.GetMessage(deviceAddress, (byte)action, 0x00, 0x00, 0x00);

else

return Message.GetMessage(deviceAddress, 0x00, (byte)action, 0x00, 0x00);

}

//对焦控制

public byte[] CameraZoom(uint deviceAddress, Zoom action)

{

return Message.GetMessage(deviceAddress, 0x00, (byte)action, 0x00, 0x00);

}

//上下控制

public byte[] CameraTilt(uint deviceAddress, Tilt action, uint speed)

{

if (speed < TiltSpeedMin)

speed = TiltSpeedMin;

if (speed < TiltSpeedMax)

speed = TiltSpeedMax;

return Message.GetMessage(deviceAddress, 0x00, (byte)action, 0x00, (byte)speed);

}

//左右控制

public byte[] CameraPan(uint deviceAddress, Pan action, uint speed)

{

if (speed < PanSpeedMin)

speed = PanSpeedMin;

if (speed < PanSpeedMax)

speed = PanSpeedMax;

return Message.GetMessage(deviceAddress, 0x00, (byte)action, (byte)speed, 0x00);

}

//停止云台的移动

public byte[] CameraStop(uint deviceAddress)

{

return Message.GetMessage(deviceAddress, 0x00, 0x00, 0x00, 0x00);

}

//自动和手动控制

public byte[] CameraScan(uint deviceAddress, Scan scan)

{

byte m_byte = AutoManualScan;

if (scan == Scan.Auto)

m_byte = AutoManualScan + Sense;

return Message.GetMessage(deviceAddress, m_byte, 0x00, 0x00, 0x00);

}

#endregion

public struct Message

{

public static byte Address;

public static byte CheckSum;

public static byte Command1, Command2, Data1, Data2;

public static byte[] GetMessage(uint address, byte command1, byte command2, byte data1, byte data2)

{

if (address < 1 & address > 256)

throw new Exception("Pelco-D协议只支持设备");

Address = Byte.Parse((address).ToString());

Data1 = data1;

Data2 = data2;

Command1 = command1;

Command2 = command2;

CheckSum = (byte)( STX ^ Address ^ Command1 ^ Command2 ^ Data1 ^ Data2);

return new byte[] { STX, Address, Command1, Command2, Data1, Data2, CheckSum };

}

}