Siemens SIMATIC HMI TP 170A, Руководство по эксплуатации оборудования, Страница: 37 / 108

Operation of Screen Objects
5-7
TP 170A Equipment Manual
Release 12/99
5.4 Logging On and Off from the Operating Unit
Purpose
During the configuration, input fields and buttons can be protected against
unauthorized operation by assigning passwords. Important parameters and
settings can then only be modified by authorized personnel. The password is
defined at the moment the element is configured and cannot be modified via the
operating unit.
Logon
If operating elements are to be assigned password protection in the configuration,
it must be possible for the operator to log on. In this case, the function
Logon_User
must be linked with an operating element, preferably an input field, in the
configuration.
In order to access a password protected operating element during runtime, it is
necessary to log on on the operating unit. It is then possible to access all password
protected operating elements up to the point of logging off from the operating unit.
Logoff
In order to rule out operation by unauthorized personnel, the logon should not
remain active on the operating unit for too long a period of time. The following
options are available with which to log off from the operating unit:
Configured logoff time expires
If the operating unit is not operated by the user within the configured period
(logoff time), he is automatically logged off from the operating unit.
Log off of the operating unit
If the configuration links the function Logoff_User with an operating element,
the element can be used log off from the operating unit.
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