Remanent
This function block is used to save signal values persistent in a specific remanent memory, to be able to recreate these values if the PLC had to be shut down.
During the normal program operation the signal on input Value will be saved to the remanent memory every five seconds. This activity will be shown at the output bSaved by changing to HIGH for one cycle.
The PLC offers 32 byte of retentive memory. Every function block of this kind allocates a number of bytes according to its data type. If a function block tries to allocate memory beyond that maximum of 32 byte, an error message will be given and the download of the program will be aborted.
Every download of a program to the PLC will reset the whole remanent memory.
During restarting process of the PLC, the function block will read the remanent memory once in the very first program cycle and will write its content back to the signal Value.
Note
The remanent blocks write into an EEPROM memory which has a limited number of write cycles.
(For binding information please refer to the manual for the specific controller.)
Signals
| Name | I/O | Type(s) | Function |
|---|---|---|---|
| Value | I/O | BIT, WORD, LONG, FLOAT | Input signal |
| bSaved | O | BIT | Write indicator |
Visualization
If the function block cannot allocate its remanent memory, it will be depicted red in run mode.
Comment
The data type of the function block will be set by connecting the input Value.
This function block will only save single values. If a vector is connected to input Value, only the first element will be saved and a warning message will be given.