The semantic of mag defines: "The value of mag shall be updated to the current value of instMag when the value has changed according the configuration parameter db" (see page 53 of 61850-7-3).
This definition does not define when the calculation starts. Does it start when the RCB or LCB starts monitoring (enable set to true)? I guess this is what we mean. Should it use the value of that time and start calculation? Or should a RCB issue a general interrogation (client or server initiated) after it is enabled and start from that first reported value?
Clarify ... add description.
There is no need to define the details of db-calculation it is a local issue.