is it possible to add an alarm when power off the PLC ?

[Ayoub]

Hello , 

I want to add  in the alarm history a fault when One power up and power off the PLC . in the power up  of the PLC I used the SB2 and it worked. but in the power off I do not know how to do it, I tried to use even SB2 by reversing the contact but it always gives me the startup time and is not the one of the power off.

[Flex727]

I create my own alarm history rather than use the built-in alarms function, but the technique I use for this could be adapted to your needs. When I create my alarm history, I store the date and time in a vector of MIs using the "RTC To ASCII" function. If you grab the data from that vector in a ladder rung that is executed before the RTC To ASCII function, with SB 2, you will have the last date & time stored just before power loss. Grab the data again with SB 2 just after the function and you'll have the power on date & time. This can be done in 3 consecutive ladder rungs if desired.

[Ayoub]

On 4/27/2018 at 1:49 PM, Flex727 said:

Thank you Sir,
Please, can you tell me how to recover the value of MIs after having power up the plc, I already tried to do it but I did not arrive there

 

[Flex727]

Here is the way I do it. I'm logging the date and time to a data table, but you can do whatever you want with the MI vectors MI 2000 & MI 2005, such as copy the vectors to another location that won't be overwritten in the next ladder rung.