英文:
How do I view raw memory addreses of MODBUS TCP/IP holding registers in CODESYS
问题
为了一个工作项目，我需要读取一个使用CODESYS 3.5编程的IFM CR1203 PLC的一堆保持寄存器。
PLC将运行一个从设备实例，读取保持寄存器的设备将是一个运行自定义Javascript应用程序的PC，该应用程序被编程为客户端。我已经为自定义应用程序编程了MODBUS TCP/IP功能，经过测试可用（对于之前的一个项目，我必须为使用不同平台编程的不同PLC执行相同的操作）。
我的当前问题是，我需要原始存储器地址的第一个保持寄存器，但我在CODESYS IDE上找不到它。CODESYS使用一个寻址系统，使不同基于CODESYS的设备之间的通信变得容易。以下是一个解释它如何工作的链接：CODESYS MODBUS寄存器位置指南
唯一看起来可行的是来自上面的链接：
<memory position> : <number> ( .<number> )* // 取决于目标系统
但我不完全理解这一切的含义。
我也找不到有关PLC或CODESYS的任何详细解释这个主题的文档。以下是用于测试的虚拟代码片段，显示了CODESYS地址：
请问有人可以解释一下如何将值%IW0转换为原始存储器地址，例如0xFFFF吗？
英文:
For a work project, I have to read a bunch of holding registers from an IFM CR1203 PLC that is programmed using CODESYS 3.5.
The PLC will be running a slave instance and the device reading the holding registers will be a PC running a custom application programmed in Javascript to be a client. I have already programmed MODBUS TCP/IP functions for the custom application that is tested and works (For a previous project I had to do the same for a different PLC programmed using a different platform).
My current issue is that I need the raw memory address of the first holding register to do this, but I can't find it on the CODESYS IDE. CODESYS uses an addressing system that makes it easy for different CODESYS-based devices to communicate. Here is a link that explains how it works: CODESYS MODBUS register location guide
The only thing that looks like it can work is from the link above:
<memory position> : <number> ( .<number> )* // Depends on the target system
But I don't fully understand what all that means.
I also can't find any documentation on the PLC or CODESYS that explains this topic in enough detail. Here is a snippet of dummy code used for testing that shows the CODESYS addresses:
Can someone please explain to me how I can convert the value %IW0 to a raw memory address, for example, 0xFFFF?
答案1
得分: 1
在他们的文档中写道：
从主视角来看，I/O 被映射到 Modbus 寄存器，如下所示：
- %IWs 从寄存器 0 映射到 n-1，并且是可读/写的（n = 保持寄存器数量，每个 %IW 寄存器占用 2 个字节）。
- %QWs 从寄存器 n 映射到 n+m-1，只读（m = 输入寄存器数量，每个 %QW 寄存器占用 2 个字节）。
所以在您的示例中，它们应该是地址 0 和 1。
英文:
I use Machine Expert (Codesys 3.5.16) and in their documentation says:
> The I/Os are mapped to Modbus registers from the master perspective as follows:
>
> - %IWs are mapped from register 0 to n-1 and are R/W (n = Holding register quantity, each %IW register is 2 bytes).
>
> - %QWs are mapped from register n to n+m -1 and are read only (m = Input registers quantity, each %QW register is 2 bytes).
So in your example they should be address 0 and 1.
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