CAPL-将4个原始字节转换为浮点数 [英] CAPL - Converting 4 raw bytes into floating point

问题描述

CAPL-向量。

我收到消息ID 0x110，其中包含当前信息：

I receive message ID 0x110 which holds current information:

0x3E6978D5-> 0.228

0x3E6978D5 -> 0.228

当前，我可以读取数据并保存到环境变量中，以使用以下方法在面板中显示：

Currently I can read the data and save into Enviroment Variable to show in Panel using:

putValue（ slow_current，this.long（4））;

putValue(slow_current, this.long(4));

但是我不知道如何将4个十六进制字节转换为float变量，因为我不能使用地址或强制转换（ float * x =（float *）&vBuffer;）

But I don't know how to convert the HEX 4 bytes into float variable, since I cannot use address or casting (float* x = (float *)&vBuffer;)

如何在CAPL脚本中进行此转换？

How to make this conversion in CAPL script? Thanks.

推荐答案

通常，您的dbc文件应包含从原始值（在您的情况下为4B长）到物理值的转换信息。因子和偏移量定义的形式：

Typically your dbc-file shall contain conversion info from raw value (in your case 4B long) to physical value in form of factor and offset definition:

因此，您的电流物理值应按以下公式计算：
phys_val =（raw_value * factor）+偏移量

So your physical value of current shall be calculated as follows: phys_val = (raw_value * factor) + offset

注意：您定义负偏移量，然后在上面的公式中实际减去它。

Note: if you define negative offset then you actually subtracting it in equation above.

但是您似乎没有dbc文件，因此您需要自己弄清楚系数和偏移量（如果您有2个示例原始值并知道它们的物理等效项）那么它就像查找线性方程参数一样简单-> y = ax + b）。

But it seems you don't have dbc-file so you need to figure out factor and offset by yourself (if you have 2 example raw values and know their physical equivalent then it shall be as easy as finding linear equation parameters -> y = ax + b).

CAPL应该看起来像这样：

CAPL shall look like this:

variables

{
    float current_phys;
    /* adjust below values to your needs */
    float factor = 0.001 
    dword offset = -1000
}
on message 0x110
{
    current_phys = (this.long(4) * factor) + offset;
    write(current_phys);
}

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