BECKHOFF C9900-U3x0 - Manual (Page 15)

Installing the UPS
Configure the interface card C1230S
Start the TwinCAT System Manager and click with the right mouse button
onto I/O devices. Choose append device.
Choose the I/O device Beckhoff IPC (C1230-S)
In order to activate the UPS under TwinCAT, the check box Use UPS must
be selected. The wait time dictates the period of time before the PC will
shut down after failure of the external supply voltage.
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