Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 120

Processing details
■Derivative operation processing
When the operation signal (INVLD) is FALSE, this function block performs derivative operation to the value input from the
input variable IN and outputs the result from the output variable OUT_.
Condition Input (IN)
Operation
signal (INVLD)
FALSE
Input (IN)
TRUE
Input (IN)
Operation signal (INVLD)
FALSE (Valid)
TRUE (Invalid)
T: Execution cycle
T_: Derivative time (s)
IN: Input value
IN : Last input value
n-1
OUT_: Output value
OUT_ : Last output value
n-1
Ys: Initial output value
S: Laplace operator
■Operation signal
When the operation signal (INVLD) is FALSE: Derivative operation is valid.
When the operation signal (INVLD) is TRUE: Derivative operation is invalid.
Operation error
Error code Description
(SD0)
3400H An invalid operation (such as division by zero) is performed.
3402H Input data (INVLD, IN), output data, or operation constant (T_, Ys) is a subnormal number or NaN (not a number).
3403H An overflow has occurred.
8 CONTROL OPERATION
118
8.3 Derivative (M+P_D)
t
t1 t2
t
t1 t2
Output (OUT_)
T_
OUT_= ×(OUT_
T_+ΔT
OUT_ = Ys
Derivative Output (OUT_)
operation
T_•S
Output (OUT_)
1+T_•S
Ys
Output (OUT_)
Ys
-IN_ +IN)
n-1 n-1
t2
t1
0
t1 t2
t
t