Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 136

Processing details
■Bumpless transfer processing
This function block changes the values output from the output variable OUT_ from the output control value CTRLV to the
output setting value SETV smoothly when the input variable MODE (mode switching) changes from FALSE (MANUAL) to
TRUE (AUTO).
The output (OUT_) approaches the output setting value (SETV) at a ratio set with the lag time (T_).
However, when the value is within the range set by the lag band (a_) based on the output setting value (SETV), the output
(OUT) approaches the output setting value (SETV) with the primary delay filter enabled.
Condition
Mode switching (MODE) |Xp|
FALSE (MANUAL)
TRUE (AUTO)
MODE: Mode switching
OUT_: Output value
SETV: Output setting value
CTRLV: Output control value
Xq: Initial deviation
Xp: Deviation
T: Execution cycle
T_: Lag time (s)
a_: Delay band
Operation error
Error code Description
(SD0)
3400H An invalid operation (such as division by zero) is performed.
3402H Input data (MODE, SETV, or CTRLV), operation constant (T_, a_), or internal operation value (Xq, Xp) is a subnormal number or NaN (not
a number).
3403H An overflow has occurred.
8 CONTROL OPERATION
134
8.9 Bump-less Transfer (M+P_BUMP)
Xp
 Xq = CTRLV - SETV
Xp = CTRLV - SETV
|Xp| > a_
Xp=Xp'-
|Xp|  a_
Xp=
ΔT
×Xq
T_
T_
×Xp'
T_+ΔT
Output (OUT_)
OUT_ = CTRLV
OUT_ = SETV + Xp
This expression is applicable when the
following conditions are satisfied.
OUT_ = SETV, Xp = Xp'
ΔT
|Xp| ≤ ( )×|Xq|
T_
OUT_ = SETV + Xp
This expression is applicable when the
following conditions are satisfied.
OUT_ = SETV, Xp = Xp'
|Xp|  0.0001