Logging in with an RFID tag is possible, but it’s not very straightforward at the moment. I know that there is sample in unofficial BR GitHub which may help you but it’s not exactly what’ you’re looking for in that
- It uses ArUser (not MpUserX), and
- It does not use an LDAP server
The only way I know of doing this at the moment is associating an RFID token with a user in the backend and then forcing a login when the token is read. I’m not sure if this same approach would work with an LDAP server but I suspect it would be trickier.