1. When I use “PrevTime(n)”, the time difference between Prevtime and the current time is about 140 seconds, and the channel value has not changed. How often is the channel update time updated by default? Because I need to determine how often the data is updated, if it is too long, I need to determine that the channel is abnormal, and if the channel has not been updated, the status of the channel will become 0, and the value will also become 0?