Skip to content

Power Down Procedure

ingfuingfu
edited August 2021 in PLCnext Technology & PLCnext Controls
Hi,
we are working on an application based on the AXC F 1152 that will be deployed as a docker container consisting of the application and a database.
We are worried about data loss and data corruption as we didn't find any information about how to properly shut down the device or what happens in case of a power loss.
There seems to be a UPS battery installed, does the device terminates running containers properly allowing them to flush files to the storage when the power disconnects?

Comments

  • Martin - PLCnext Technology TeamMartin - PLCnext Technology Team
    The battery in the AXC F 1152 is not part of a UPS, so it is not possible to implement any automatic procedures when power is lost to the device.
    The expected behaviour of containers on the PLC during this event would be similar to the behaviour on a desktop PC running a Linux OS, when the power is removed.
    If an orderly shutdown is required, it would be necessary to add your own UPS (Phoenix Contact does some nice ones ;-), and handle a signal from that UPS to do an orderly shutdown of your container(s) when input power to the UPS is lost.
  • ingfuingfu
    Thanks for the quick reply. It's the AXC F 3152 that is supposed to a have a UPS built-in...
    Have You heard of issues with corrupt file systems using Docker so far? Our use case involves a AXC F 1152 inside a control cabinet of a machine that usually is just powered off without proper shut down.
    Can a shut down of the AXC F 1152 been triggered from within the PLC?
  • Martin - PLCnext Technology TeamMartin - PLCnext Technology Team
    It's the AXC F 3152 that is supposed to a have a UPS built-in...
    Yes, that's correct, the 3152 does have a buffer. In the event of power loss, the PLCnext Runtime uses a signal from this buffer to perform an orderly shutdown of the Runtime application.
    If you were using an AXC F 3152, you might be able to pick up the same signal to do an orderly shutdown of your application(s).
    Or, if you are using an external UPS, you can get a signal from the UPS to trigger a shutdown of your application(s).
    It is also possible to use the standard Linux "shutdown" command, if you want. Since the device does not have an on/off power switch, it will automatically restart after the shutdown, which might not be what you want.
  • ingfuingfu
    So, the standard shutting down procedure is just cuting power, right?
  • Martin - PLCnext Technology TeamMartin - PLCnext Technology Team
    Yes, that's right. PLCs are generally used in production applications that are designed to run for a long time (possibly years) without power interruption, so a complete shutdown is expected to be a rare event. The PLCnext Runtime is designed to handle this type of event without problems. We can't guarantee that user-installed applications will do the same.
Sign In or Register to comment.