There are four types of setpoint:
Only the two last setpoints can be used with the 3 single loops or the Auto Selector loop.
A local setpoint is a setpoint written by a Man-Machine Interface.
A remote setpoint is a setpoint produced by a process.
Block Diagram of the Branch
Block diagram of the setpoint processing branch.
-
The local value tracks the value of the remote setpoint in order to avoid bumps on the change of operation.
-
If the address of the remote setpoint is not given, local mode is forced.
-
To avoid changes which are too abrupt, the speed of the setpoint can be limited.
-
By default, the setpoint is limited to the loop scale. A more restrictive limit can be fixed.
-
When the loop controller is in manual mode, the setpoint can track the process value.
How the Initialization Works
-
On start-up, the associated data is first updated before the launch of the first process of this branch.
-
If the process value input address is not set, processing is performed on the simulated value initially set to zero.
-
On initialization, there is a consistency check on the configuration entered. If there is a problem with the configuration, the loop remains in a state of initialization.
Operation of Execution Check
The two faults checked by setpoint processing are parameter errors (not written in floating point format) and internal calculation errors (division by zero, overflow, etc.). When such a fault appears:
-
The result of the SP setpoint processing is frozen.
-
Warnings are displayed.
-
These errors are not considered to be serious at the level of the control loop; loop controller and output value calculation is performed with the value of the frozen setpoint.
-
Calculation of the SP setpoint restarts as soon as the fault disappears.
-
