Always programmers lock the programmed CPU by a password to protect their software.
As always we say, the software is the programmer know-how, so it’s for him. The
client own the CPU as a hardware and also the application. i.e. he could use the
software for his application but he is not authorized to modify, delete or add
any thing to the software without notifing the programmer.
So, Siemens make passwords of the CPUs (in case of selecting this option) to
protect the programs from un-authorized access. To access the software, you
must ask the programmer for the password!
As I told before that the client own both the application and also the H/W.
So, there is a master password you can use to erase and only erase the software
from the CPU and then, the CPU will be returned into factory setting. i.e. a blank
CPU. You can pragram it as you like. Without this password. So, it will not help
you to upload the software!
The master erasing password: CLEARPLC
忘记 PLC 密码怎么办？
如果忘记 PLC 密码，您必须清除 PLC 存储区，重新载入程序。清除 PLC 存储区使 PLC 进入 STOP（停止）模式，
并将 PLC 复原为工厂设置的默认值，PLC 地址、波特率和实时时钟除外。
欲清除 PLC 中的程序：
1. 选择 PLC > 清除叄–lear）菜单命令，显示“清除”对话框。
2. 选择所有的复选框，并点击“确认”按钮核实采取的措施。
3. 如果密码已被配置，STEP 7-Micro/WIN 会显示一个密码验证对话框。欲清除密码，在密码验证对话框中输入
本文关键字：密码 PLC入门，plc技术 - PLC入门
