Retain Value after Power Loss

I just have a beginner's question about the value retention during power loss (either in PC RT or S7-300).

If I program say, a PID and configure it's faceplate via simple IO fields, would the values be retained in the respective PID Data Block (or any interface DB I create for tagging) after *any* powerloss? If this is so, since the IO fields are read/write, then there's no need to worry on the PC/HMI side, since it will just read the retained value in the PLC DB, thus will reflect the retained value.

But if this is not the case, then what should I do to secure the values from being loss when there's a power failure? Is there something to do in the HMI side to retain the input values aside from just configuring simple IO fields?

Thanks much!

First, I would like to thank you for your always immediate reply, even in the shallow questions of mine!hehe.. It's much appreciated!

On the screenshot you've given, it seems to be saying something about retentive properties of memory bits, timers, and counters, but not about Data Blocks. Though, it has been said that Data Block is by default retentive if it has no optional property of "non-retentive", is this accurate? Also what if I re-download the whole program including DBs, would the current DB values be replaced by the default DB values (what you've configured, in inside the DB, in each line of DB addresses)? What about if I do a Mres [the 3 times (PLC mode) switch down with a hold], what happens to the current DB values?

I'm visualizing the retentive behavior of process input parameters (e.g. PID parameters) interfaced/tagged in PLC DBs, during any events such as PLC/PC/HMI power loss, project download, memory reset, etc., in anticipation and preventive actions/configuration with regards to data losses.

In short, what do I do if I want my process input parameters (in DBs) to remain in its current value during *any* events, perhaps except if I really intended to erase the values?

Thanks much!

First, I would like to thank you for your always immediate reply, even in the shallow questions of mine!hehe.. It's much appreciated!

On the screenshot you've given, it seems to be saying something about retentive properties of memory bits, timers, and counters, but not about Data Blocks. Though, it has been said that Data Block is by default *retentive* if it has no optional property of "non-retentive", is this accurate? Also what if I re-download the whole program including DBs, would the current DB values be replaced by the default DB values (what you've configured, in inside the DB, in each line of DB addresses)? What about if I do a Mres [the 3 times (PLC mode) switch down with a hold], what happens to the current DB values?

I'm visualizing the retentive behavior of process input parameters (e.g. PID parameters) interfaced/tagged in PLC DBs, during any events such as PLC/PC/HMI power loss, project download, memory reset, etc., in anticipation and preventive actions/configuration with regards to data losses.

In short, what do I do if I want my process input parameters (in DBs) to remain in its current value during *any* events, perhaps except if I really intended to erase/reset the values?

Thanks much!