The firmware problem of AXC F 2152

PLCnext Technology & PLCnext Controls
1

The controller AXC F 2152 is used in some logistics projects in China. The factory firmware of AXC F 2152 is 2020.0. Later，we updated the firmware of the controller to 2020.3. Because there was a power failure in the factory(the power was unstable),the firware of the controller was reset to the factory(2020.0). The program and the configuration in AXC F 2152 was OK, but the retain data was also reset to the initial value. Would you like to find the reason for us? Thank you in advance.

2

Hi lijixian, I guess this is related to the handling of the partitions of the PLCnext Controls. The SD card (internal/external) has three bootable partitions:

                                               1. Golden Image (Read Only, just backup)
                                               2. Partition A - normal operation
                                               3. Partition B - normal operation

After first unpacking the PLC does the system starting up with the initial firmware with Partition A and this is now you working partition which is booted all the time you start the PLC.
In case of a firmware update is the update performed on Partition B and after the updated finished successfully does the system switch the primary Partition from A to B. Means, after now restarting the PLC will the system boot the image based on Partition B, but Partition A is still available with the previous firmware. If (for whatever reason) the active Partition gets corrupted, will the system boot once again from the A Partition with the previous firmware. The system is in that way always available, but the retains are of course lost.
If the application is not created with a compatible template, will the application not start. We’ll document this feature a bit more in detail with on of the next updates of the PLCnext Info Center. Take care Frank

3

Hi Frank, Thank you very much. I have understood it. Best Regards Li Jixian

4

Hello Frank Thank you for your explain. I am also interested about this topic. 1.could you describe what external conditions will trigger this switch from Partition B to Patition A? at least there are two cases as Lijixian feedback occur in our different customer application site, and the retain variables turn to the inital value, and the program still runing,cause the control disorder. 2.and you mention about the SD card,If we don’t use SD card ,just download the program to the RAM of PLCnext ,it won’t gets corrupted? Thanks very much!

5

Hi 602129929, basically it works like on your private PC were you’ve maybe several bootable disks inside.

The bootloader tries to startup the primary partition and if that fails it will try to start the next and this is exactly how also the PLCnext bootloader works. Important is also to know that every PLCnext control comes with an internal SD card, so even if there is no external card inserted there is always a storage device available.
When you download an application (normal or downloadchange) will always be the new files be stored on the card. So, the important questions is of course how could that happen?
Even when the filesystem of PLCnext is very robust it might happen that due to a power issue during a write process could get corrupted.
Therefore we strongly recommend to use an independent power supply for the PLC (UL) to separate the field to the control. But every case is a bit different, if you like you can come back to me directly by mail (fwalde@phoenixcontact.com) to go a little bit deeper… Take care Frank