Rockwell-automation 57C620 AutoMax Programming Executive Version 3.8 Instrukcja Użytkownika Pobierz pdf (Strona 269)

NĆ1Tokens and Locking





Tokens provide a means of writeĆprotecting the databases and tasks for one or

more racks or an entire system when using the AutoMax Programming Executive

in a network environment. Locking will prevent more than one user at a time from

changing the same database information.



When more than one copy of a file exists, there is the potential that the various

copies will be modified independently. This problem can occur in AutoMax when

part or all of a system is transferred to another workstation. To avoid losing

independent changes, only one copy can be considered the source" copy. All

other copies must be considered to be readĆonly. Tokens are used in AutoMax to

ensure that only one copy can be modified.

token is an abstract entity which represents the ability to modify a group of files.

There will be one token to represent the system database group and the system

and section documentation files, and a separate token for each rack and its

associated files. If a copy of the rack file holds" the token, that copy can be

modified.

If a copy does not hold the token, it cannot be modified. Only one copy

of the system files or of a rack file can hold the token. If a user attempts to make

modifications without the token, the user will receive an error message like the

following:

When a system or rack is created, a token is created along with it. Whenever the

system (or rack) is transferred using the Transfer command in AutoMax, the user

has the option of transferring the token with it. If the token is transferred out, the

original copy becomes readĆonly and only the destination copy can be modified.

1 2 ... 264 265 266 267 268 269 270 271 272 273 274 ... 297 298

Brak uwag

Rockwell-automation 57C620 AutoMax Programming Executive Version 3.8 Instrukcja Użytkownika Strona 269