R32SFCPU word & double word data

[Pruthviraj]

why do all my word & double word global label go to zero when i download my R32SFCPU plc?

[Crossbow]

Are you downloading device memory?  Are they set up in parameters to be latched?  Several reasons possible...

[Parky]

you should not download the data memory unless you have uploaded a copy previously as the data stored on disk may not be the same as in the PLC.

For example assume you have uploaded to your PC the Data Memory (Normally called MAIN) but you have changed things like stored data in a recipe etc. downloading from your PC to PLC will overwrite it to a previous data.

Normally if making changes to a program only download the plc logic & perhaps the PLC Parameters etc. when you have set any data via an HMI or within the program in D words for example take an upload of that data as a start point if you need to replace the plc or it loses it's memory.

also some data areas are non retentive so you need to check the PLC Parameters & if required set the latch ranges & download the parameters. ensure retentive (Latched) data is in the range set in those parameters.

 

[Pruthviraj]

when I download even though I have not selected the device memory it goes back to 0 & for the parameter please check below image and let me know if any corrections are required. 

[Crossbow]

Your photo does not show the Detailed Settings for latched memory areas, so we cannot tell what you have configured to be battery backed.  Also keep in mind any changes to parameters typically require a power cycle to take effect, and that will zero out all non retentive addresses.

[Parky]

Double clock on Device/label setting area & there is the latch ranges

[Pruthviraj]

Will this work?

[Parky]

Yes sort of you need to assign latch areas for retention of data or when the PLC is powered down ones that are not latched will reset to zero & to get stored values off line you have to give the global label an actual address & compile & download, read the data main to your project & you will have a copy of the data in those registers as the symbols without an actual address when compiled these are allocated special addresses at compile time so you do not know which ones are which.