Pidd (Pid With Derivative Decay) - IDEC MICROSmart FC6A Series Ladder Programming Manual

19: PID C I
ONTROL NSTRUCTION

PIDD (PID with Derivative Decay)

Executes PID control and outputs that result. The PID control parameters stored in the control registers are handled as data type
F (float), and fine adjustments can be made to the control parameters such as proportional gain, integral gain, and derivative gain.
Multiple PIDD instructions can also be combined to execute the cascade control.
PIDD ** S1
*****
Operation
When the input is on, PID control is performed.
Knowledge of PID control is required to use the PIDD instruction. If this instruction is used without an
Warning
understanding of PID control, there is a possibility of control that was not intended by the user. Please use the
PIDD instruction with a full understanding of PID control and the PIDD instruction.
When performing feedback control using the PIDD instruction, emergency stop and interlocking circuits must
be configured outside the FC6A Series MICROSmart according to the user application. If these are configured
in the internal circuit and the process variable is not input correctly, there is a risk of no longer being able to
perform proper feedback control, which may damage connected devices or cause accidents.
The PIDD instruction cannot be used in an interrupt program. If the instruction is used in an interrupt program, a user
Caution
program execution error occurs, the execution of the instruction is canceled, and the next instruction is executed.
For user program execution errors, see "User Program Execution Errors" on page 3-10.
Note: A maximum of 32 PIDD instructions can be used in a user program.
Valid Devices
The control register uses 100 words, and the control relay uses 32 internal relays.
Device
S1 (Source 1)
S2 (Source 2)
S3 (Source 3)
*1 Special data registers cannot be used.
*2 Special internal relays cannot be used. Only 0 can be specified as the first digit of the internal relay number. 1 to 7 cannot be specified.
19-26
S2 S3 SP
***** ***** *****
Function
Control registers
Initialization input
Control relays
FC6A S MICROS
ERIES MART
PV MV
***** *****
I Q M
— — —
X — X
— — X
L P M
ADDER ROGRAMMING ANUAL
R T C D P
*1
— — — X —
— — — — —
*2
— — — — —
FC9Y-B1726
Constant Repeat
— —
— —
— —