Signal Processing In The Pid Function Block - Endress+Hauser iTEMP TMT 165 FOUNDATION Fieldbus Betriebsanleitung

11 Appendix
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of the PID Function Block depends on the automation task. The following can be
realised: basic controls, feedforward control rejection, cascade control, cascade
control with limiting.
The possibilities available for processing measured values within the PID Function
Block include: signal scaling and limiting, operating mode control, actuating, limiting
control, limit detection and signal status propagation.
• IN = Input of the controlled variable from another function block.
• CAS_IN = Input of the remote setpoint value from another function block.
• BKCAL_IN = Input of the feedback value and status from the output BKCAL_OUT of the
subsequent function block, to prevent reset window and to initialise the control loop.
• TRK_IN_D = Discrete input for activating the external output tracking function.
• TRK_VAL = Input for the external value for tracking from another function block.
• FF_VAL = Input for the disturbance variable from another function block. (Feedforward control)
• OUT = Output value and status (actuating variable) of the PID Function Block.
• BKCAL_OUT = Output for the feedback value and status transferred to the input BKCAL_IN of the
upstream function block to prevent reset window and to provide bumpless transfer to
closed loop control.

11.7.1 Signal processing in the PID Function Block

The diagram shows the internal structure of the PID Function Block:
Fig. 11-4: Schematic structure of the PID Function Block
FOUNDATION Fieldbus temperature transmitter
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