To control the variable setting the process value, according to the law of linearly increasing function – the functional block Ramp.
Processes the input values of the process and generates an analog output signal, which is the setting for the operation of a particular controller. Linear-incremental function is designed for a time-consuming achievement of a given setpoint by a technological process.
The unit supports the possibility of temporarily stopping the collection / reduction of the linearly increasing function, depending on the need of the technological process (for example, without the need for regulation).
The logic of the function block allows to achieve the floating set point (FSP) to the static set point (SP) for the set time (RAMP_TIME). This slowdown by the control of the technological process is required for inertial processes.
The slope angle of the linearly-increasing function with the initial action (START) occurs in time (RAMP_TIME), all subsequent static settings (SP) jumps occur at a rate of one degree per minute.
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The output from the function block serves as the setting for the controller. Variables FSP_SP FSP_PV, provide visualization of the values assigned to the body of the output. FSP_SP is assigned if the process measurement has passed the SP boundary, and FSP_PV if the input of the START block is set to FALSE. If the variable INDIRECT is activated (TRUE), then the geometric arrangement of the slope angle of the FSP to the opposite and the function changes. From the choice of the value of this input depends the nature of the operation of the unit linearly increasing or linearly decreasing function.
I spread the code of this FB RAMP