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[实际项目2] 从西门子PLC中读取曲线数值并绘图

news 来源：原创 2025/6/7 11:25:54

一、项目背景说明：
有的设备中，需要读取PLC的数据并绘图（比如压装曲线），本案例做了一个压装曲线的demo，效果见下图：

淘宝网上商品的连接如下：https://item.taobao.com/item.htm?ft=t&id=934043951571&spm=a21dvs.23580594.0.0.3c3a2c1bQpFgHX&skuId=5824162524427

西门子PLC的曲线绘制监控软件（含源代码）-商品号934043951571-淘宝网

二、使用方法：

1. PLC这边在DB块中做如下的变量：

整个流程的逻辑是：

a). PC->PLC： Ready=true

b). PLC->PC: Start =true

c). PC->PLC: StartAck=true, 并且把Ready=false; PC开始记录点；同时PLC开始动作

d). PLC->PC: Stop=true

e). PC->PLC: StopAck=true.

f). PLC->PC: Stop=false

g). PC->PLC: StopAck=false. Ready = true.

本demo中：plc代码如下：

CASE "DB2_XYCurveData"._step OF0:IF "DB2_XYCurveData".PLC_to_PC.Start THEN"DB2_XYCurveData".Displacement := 0;"DB2_XYCurveData".Force := 0;"DB2_XYCurveData".TimeDuration := 0;"DB2_XYCurveData"._step:= 1;END_IF;1:IF "DB2_XYCurveData".PC_To_PLC.AckStart THEN"DB2_XYCurveData"._step := 2;END_IF;2:"DB2_XYCurveData".TimeDuration := "DB2_XYCurveData".TimeDuration + 0.01;"DB2_XYCurveData".Displacement := "DB2_XYCurveData".TimeDuration;"DB2_XYCurveData".Force :=100* SIN(3.1415 * ("DB2_XYCurveData".TimeDuration) / 20.0)+50* SIN(3.1415*4 * ("DB2_XYCurveData".TimeDuration) / 20.0);IF ("DB2_XYCurveData".TimeDuration >= 10) THEN"DB2_XYCurveData"._step := 3;END_IF;3:"DB2_XYCurveData".PLC_to_PC.Stop := 1;IF "DB2_XYCurveData".PC_To_PLC.AckStop THEN"DB2_XYCurveData".PLC_to_PC.Start := 0;"DB2_XYCurveData".PLC_to_PC.Stop := 0;"DB2_XYCurveData"._step := 4;END_IF;4:IF NOT "DB2_XYCurveData".PC_To_PLC.AckStop THEN"DB2_XYCurveData"._step := 0;END_IF;
END_CASE;

2.只需要在本项目的config文件中，把DB2.DBB0配置进去即可。

三、主要技术点

1.主要使用LiveCharts这个第三方库进行曲线绘制。

<Border Grid.Row="0" Grid.Column="1" BorderBrush="Black" Margin="10" BorderThickness="1"><lvc:CartesianChart DisableAnimations="True" Hoverable="False" DataTooltip="{x:Null}"><lvc:CartesianChart.Series><lvc:LineSeries Values="{Binding XYChart01_Values}"  PointGeometry="{x:Null}" LineSmoothness="1" Fill="Transparent" ScalesYAt="0"/><lvc:LineSeries Values="{Binding XYChart01_RangeValues}" PointGeometry="{x:Null}" LineSmoothness="0" Fill="Transparent" ScalesYAt="0" Stroke="GreenYellow" Visibility="Collapsed" /></lvc:CartesianChart.Series><lvc:CartesianChart.AxisY ><lvc:Axis  ShowLabels="True" Foreground="Black" Title="压力(N)" FontSize="14" FontWeight="Light" LabelsRotation="0" MaxValue="500" MinValue="0"><lvc:Axis.Separator><lvc:Separator  StrokeThickness="0.5" Stroke="Orange" StrokeDashArray="1" /></lvc:Axis.Separator></lvc:Axis></lvc:CartesianChart.AxisY><lvc:CartesianChart.AxisX><lvc:Axis Position="LeftBottom" ShowLabels="True" Foreground="Black" Title="位移(mm)" FontSize="14" FontWeight="Light" LabelsRotation="1" MaxValue="10" MinValue="0"><lvc:Axis.Separator><lvc:Separator  StrokeThickness="0.5" Stroke="Orange" StrokeDashArray="1" Step="0.5"/></lvc:Axis.Separator></lvc:Axis></lvc:CartesianChart.AxisX></lvc:CartesianChart>
</Border>

2. 周期性的从PLC中读取18个的内容，解析出其中的XY值以及握手协议值。

3. 在PC中进行握手协议的编写：

 public void Run(){PlcConnection =  this.PLCData.ByteArrayTag.Parent.Parent.IsClosed==false;if (Step==0 && this.PLCData.PcToPlcReady==false){(this.PLCData.ByteArrayTag.Parent.Parent as SiemensTCPReader).WriteBit(Addr_PcToPlc_Curve1StartResponse, false);(this.PLCData.ByteArrayTag.Parent.Parent as SiemensTCPReader).WriteBit(Addr_PcToPLC_Curve1Ready, true);(this.PLCData.ByteArrayTag.Parent.Parent as SiemensTCPReader).WriteBit(Addr_PcToPlc_Curve1StopResponse, false);}//启动if( this.PLCData.PlcToPcStart==true && PlcToPcStartOld==false){(this.PLCData.ByteArrayTag.Parent.Parent as SiemensTCPReader).WriteBit(Addr_PcToPlc_Curve1StartResponse, true);(this.PLCData.ByteArrayTag.Parent.Parent as SiemensTCPReader).WriteBit(Addr_PcToPLC_Curve1Ready, false);isCurve01Drawing = true;Curve01DataRead();Step = 1;}PlcToPcStartOld = this.PLCData.PlcToPcStart;if (this.PLCData.PlcToPcStop  ){isCurve01Drawing = false;if (this.PLCData.PcToPlcStopAck==false){(this.PLCData.ByteArrayTag.Parent.Parent as SiemensTCPReader).WriteBit(Addr_PcToPlc_Curve1StartResponse, false);(this.PLCData.ByteArrayTag.Parent.Parent as SiemensTCPReader).WriteBit(Addr_PcToPlc_Curve1StopResponse, true);}}if (this.PLCData.PlcToPcStop==false && this.PLCData.PcToPlcStopAck == true){isCurve01Drawing = false;  (this.PLCData.ByteArrayTag.Parent.Parent as SiemensTCPReader).WriteBit(Addr_PcToPLC_Curve1Ready, true);(this.PLCData.ByteArrayTag.Parent.Parent as SiemensTCPReader).WriteBit(Addr_PcToPlc_Curve1StopResponse, false);}                      }