System Programming
HI 803 211 E Rev. 1.01.00 Page 81 of 110
6.1.3.7 Locking and Unlocking the Resource
Locking the resource locks all functions and prevents users from accessing them during
operation. This also protects against unauthorized manipulations to the user program.
Unlocking the controller deactivates any locks previously set, e.g., to perform work on the
controller.
The three system variables Read-only in Run, Reload Deactivation and Force Deactivation are
used to lock the PES, see Table 26.
If all three system variables are TRUE, no access to the controller is possible. In this case, the
controller can only enter the STOP state by restarting all processor modules. Only then can a
new user program be loaded. The example describes a simple case, in which a key-operated
switch is used to lock or unlock all interventions to the resource.
Example: To make a controller lockable
1. Define a global variable of type BOOL and set its initial value to FALSE.
2. Assign the global variable as output variable to the three system variables Read-only in Run,
Reload Deactivation and Force Deactivation.
3. Assign the global variable to the channel value of a digital input.
4. Connect a key switch to the digital input.
5. Compile the program, load it into the controller, and start it.
► The owner of a corresponding key-operated switch is able to lock and unlock the controller. If
the corresponding digital input module fails, the controller is automatically unlocked.
This simple example can be modified using multiple global variables, digital inputs and key
switches. The permissions for forcing, reload and other operating functions can be distributed
on different keys and persons.
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