1-second UPS (Uninterruptible Power Supply)

Technical concept

The 1-second UPS is an UltraCap capacitor, which, in the event of a voltage outage, continues to supply power to the processor for approx. 4 to 5 seconds, so that persistent data can be saved. Data saving generally takes less than 4 to 5 seconds. However, due to ageing of the components used, one should assume that the UPS can provide power for a maximum of 1 second. You can assume that data saving continues to work smoothly, even after many years. If you save data yourself, we recommend that this should take place within 1 second. Should it take longer, we would advise against it.

The 1-second UPS supplies neither the K-bus nor the E-bus with power. Please note that the data of these devices may already be invalid when the 1-second UPS is activated. Also, the fieldbus system (or Ethernet) may not work or not work properly once the 1-second UPS was activated.

Saving of the persistent data only takes place in conjunction with the function block FB_S_UPS_CX80xx. This block must be called cyclically. We strongly recommend using the default values for the block.

Saving and loading persistent data

The persistent data are stored on the SD card as a wdp file. When the PLC starts up, the wdp file is loaded from the SD card, saved there as a wd~-file (backup), and then deleted. Another current wpd file is not written until the system is shut down or the 1-second UPS is activated. If no wdp file is present when the CX starts up, the persistent data are invalid and are deleted (default setting).
The reason is that the 1-second UPS was activated before the TwinCAT PLC was started during startup of the CX. In this case no persistent data were saved, since the system was unable to ensure sufficient buffer time for saving the data.

Loading a backup of the persistent data

To load the persistent data from the backup (wp~-file), it has to be enabled in the System Manager.

1-second UPS (Uninterruptible Power Supply) 1:

Or via the following registry entry:

[HKEY_LOCAL_MACHINE\SOFTWARE\Beckhoff\TwinCAT\Plc]"ClearInvalidPersistentData"= 0

The default factory setting is "1".

Checking whether current persistent data (from wdp file) or saved persistent data from the backup (wd~-file) were loaded

In this example, the CX8090 indicates via the ERR LED whether the persistent data were loaded. The LED cannot be used for other CX8xxx models.

IF systeminfo.bootDataFlags.4 AND NOT
systeminfo.bootDataFlags.5 THEN

   
F_CX8090_LED_ERR(eLED_GREEN_ON);    (* persistent
data is OK *)

ELSIF systeminfo.bootDataFlags.4 AND systeminfo.bootDataFlags.5
THEN

   
F_CX8090_LED_ERR(eLED_RED_ON);        
(* load backup persistent data *)

ELSE

    F_CX8090_LED_ERR(eLED_RED_FLASHING_200ms); (* no
persistent data *)

END_IF
1-second UPS (Uninterruptible Power Supply) 2:

Purpose of the 1-second UPS

The 1-second UPS should only be used for managing the persistent data. Other applications are not supported and are not covered by our complaints procedure. Retain data cannot be used for the 1-second UPS!