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System Manual Modular Systems
6 User Program
HI 800 191 E Rev. 2.02
Page 45 of 114
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Absolutely take the following restrictions into account when forcing or evaluating online
tests performed with forced global variables:
Global Variables
To force a global variable, the following conditions must be met:
The corresponding force switch is set.
Forcing was started.
If forcing was started, a change to the force switch has an immediate effect.
If forcing was started and the force switch is set, a change to the force value has an immediate
effect.
Global forced variable have the following characteristics:
Outputs and communication protocols receive the force value as long as the variable is
being forced.
The following conditions apply for a user program reading and writing the variable:
-
The force value is used until the user program writes a new process value. After that
moment, the process value applies for the remaining duration of the user program cycle.
The force value applies then again in the following user program cycle.
-
If the user program does not write any process value, the force value continues to be
used as the new process value, even after the end of the forcing process! The previous
process value is no longer valid.
Time Limits
A time limit can be defined for global forcing. Once the defined time has expired, the controller
stops forcing values.
It is possible to define how the HIMatrix system should behave upon expiration of the time limit:
The resource stops.
The resource continues to operate.
Local Variables
Local variable forcing is limited to the
Edit Local Process Value
command. This command
directly changes the value of variables without the need to set a force switch or to start forcing.
Additionally, no time limit can be configured for defining the validity of a used value.
The new process value set with this command (i.e., the force value) applies until one of the
following events occurs:
The user program overwrites the value with a new process value.
A new value is entered.
The user program is stopped.
The user program is restarted.
Force Editor
The SILworX Force Editor displays all the variables for which forcing is allowed. Global and
local variables are grouped into two specific tabs.
The tab for global variables can be used to configure the force values and set the force
switches.
The tab for local variables can be used to define the local process value.