The Siemens S7-400 redundant PLC cannot establish a connection
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After the step7 hardware configuration is online, all hardware on the redundant rack appears in gray (as shown in Figure 1); when double-clicking on the CPU, a message appears on the panel stating that no connection can be established (see Figure 2). Additionally, all the on-site indicator lights are functioning properly; it’s just that the TX/RX lights on the communication card flash more slowly than those on the normal rack on the left side. We have already replaced the CPU, the communication card, and the network cable, and nothing seems to be wrong. In the hardware configuration, the CPU model is 417-4h, while the CPU model installed on-site is 417-5h. I’m not sure if this is the cause, but another chassis is configured in the same way and everything works fine there. Why can’t the backup rack be connected?
The configuration is inconsistent; please update the hardware settings
You mean that in the software it’s set to 417-4h, but on-site it’s 417-5h, right? The manufacturer said it has no impact; due to a software version issue, it’s only 417-4h.
Using the configuration for 417-4 with a CPU of type 1.417-5 will result in problems; Siemens’ software compatibility is based on CPUs being of the same major version. For example, hardware from version 4.3 can be used with configuration from version 4.1, but a CPU of type -5H belongs to version V6, and using V4 version software with it will cause unexpected issues. 2. You are connected to the second CPU; you need to switch to connecting to CPU 2 in the menu above, otherwise, it defaults to connecting to the first CPU.
Using the configuration for 417-4 with a CPU of type 1.417-5 will result in problems; Siemens’ software compatibility is based on CPUs being of the same major version. For example, hardware from version 4.3 can be used with configuration from version 4.1, but a CPU of type -5H belongs to version V6, and using V4 version software with it will cause unexpected issues. 2. You are connected to the second CPU; you need to switch to connecting to CPU 2 in the menu above, otherwise, it defaults to connecting to the first CPU.
Using the configuration for 417-4 with a CPU of type 1.417-5 will result in problems; Siemens’ software compatibility is based on CPUs being of the same major version. For example, hardware from version 4.3 can be used with configuration from version 4.1, but a CPU of type -5H belongs to version V6, and using V4 version software with it will cause unexpected issues. 2. You are connected to the second CPU; you need to switch to connecting to CPU 2 in the menu above, otherwise, it defaults to connecting to the first CPU.
Excuse me, regarding what you mentioned about “switching to CPU 2 from the menu above”, where can I make this switch? Please give me some guidance. Thank you
Excuse me, regarding what you mentioned about “switching to CPU 2 from the menu above”, where can I make this switch? Please give me some guidance. Thank you
Excuse me, regarding what you mentioned about “switching to CPU 2 from the menu above”, where can I make this switch? Please give me some guidance. Thank you
It is recommended to upgrade Step7 to a version after 5.5sp2; the current highest version is 5.5sp4