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 };
}
}
