Siemens SIMATIC RF310M Function Manual page 57

Note
Writes tag data whereby both internal and user-specific areas may be accessed.
RF310 specific banks UID and CONFIG Data are not writeable, and will return with error
exception.
A valid tag ID must be specified for a tag currently within the field before you can write data,
or if no tag ID is specified, the first tag within the field will be written.
Version information
Supported in RFID Reader Interface: since V1.0
Mobile Readers
Function Manual, 12/2010, J31069-D0198-U001-A2-7618
RFID Reader Interface Reference
3.4 IRfReaderApi
57