Overview Shift register

This block shifts values through a chain of outputs on each clock pulse. With every pulse the value at input WT moves to output W1, the previous value of W1 moves to W2 and so on; the value of the last position drops out. This way the most recent values are available at the same time, for example to judge a trend or to compare several measurements. The content is stored persistently and is available again after a restart of the controller.


Inputs

WT Value Value that is shifted in.
TA Clock A rising edge (change from 0 to a value other than 0) shifts the register. Only effective with shifting mode “Clock input”.
RS Reset A rising edge sets all positions to the start value.



Outputs
W1..Wn Value W1 is the most recently shifted-in value, the last output is the oldest one. The number of outputs corresponds to the parameter Length.



Parameters
Length Number of positions of the shift register, 2 to 16.
Start value Value that all positions get after a reset.
Shifting mode
  • Clock input (rising edge): the register shifts as soon as input TA changes from 0 to a value other than 0.
  • Change at input Value: the register shifts as soon as the value at input WT changes. The clock input is then not needed.
Store persistently Stores the content of the register so that it is available again after a restart of the controller. It is saved cyclically at most once per hour and when shutting down. If the length is changed afterwards, the register starts with the start value again.

See also: Sliding average, Trend

See also common parameters of all function blocks.