Siemens SIMATIC RF310M Function Manual page 55

Note
Reads tag data whereby both internal and user-specific areas may be accessed.
A valid tag ID must be specified for a tag currently within the field before you can read data,
or if no tag ID is specified, the first tag within the field will be read.
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
55