IDEC MICROSmart FC6A Series Ladder Programming Manual page 420

19: PID C I
ONTROL NSTRUCTION
When Cascade Control - RSP (S1+4, S1+5) is selected
The PIDD instruction becomes Cascade Control Mode. Cascade Control Mode Select (S3+3) will be on, Manual Mode Select
(S3+1) will be off, and Auto Mode Select (S3+2) will be off.
Store the set point in Remote Set Point (RSP) (S1+4, S1+5) in the range of 0.0 and 100.0%. When another PIDD instruction is
specified as Master PIDD No., Output Manipulated Variable (MV) (S1+16, S1+17) of the specified PIDD instruction is
automatically loaded into Remote Set Point (RSP) (S1+4, S1+5).
Remote Set Point (RSP) (S1+4, S1+5) will be converted to the full scale of SP Lower Range Value (S1+44, S1+45) to SP Upper
Range Value (S1+46, S1+47). If the converted set point is higher than SP High Limit (S1+28, S1+29), the set point will be SP
High Limit. If the converted set point is lower than SP Low Limit (S1+26, S1+27), the set point will be SP Low Limit. The
converted set point is stored in Set Point (SP) (S1+2, S1+3).
Remote Set Point (RSP)
(S1+4, S1+5)
0.0 to 100.0%
4. Control Action (S3+0)
Select Reverse Control Action or Direct Control Action. When Reverse Control Action is selected, Control Action (S3+0)
will be off. When Direct Control Action is selected, Control Action (S3+0) will be on.
For Reverse Control Action, when PIDD instruction Process Variable (PV) becomes larger than Set Point (SP), Output
Manipulated Variable (MV) becomes smaller. Reverse Control Action is used for applications such as heating control.
For Direct Control Action, when PIDD instruction Process Variable (PV) becomes larger than Set Point (SP), Output Manipulated
Variable (MV) also becomes larger. Direct Control Action is used for applications such as cooling control.
5. Kp Dependent (S3+8)
Select Dependent or Independent. When Dependent is selected, Kp Dependent (S3+8) will be on. When Independent is
selected, Kp Dependent (S3+8) will be off.
When Kp Dependent is selected, the integral and derivative actions grow larger in proportion to Kp (Gain) (S1+6, S1+7). When
Kp Independent is selected, Kp (Gain) (S1+6, S1+7) has no effect on the integral and derivative actions.
6. SP High Limit (S1+28, S1+29), SP Low Limit (S1+26, S1+27)
Sets the upper limit and lower limit of Set Point (SP) (S1+2, S1+3).
If the value of Set Point (SP) (S1+2, S1+3) is higher than SP High Limit (S1+28, S1+29), the PIDD control set point will be SP
High Limit. If the value of Set Point (SP) (S1+2, S1+3) is lower than SP Low Limit (S1+26, S1+27), the PIDD control set point
will be SP Low Limit.
SP High Limit (S1+28, S1+29) and SP Low Limit (S1+26, S1+27) are set as data type F (float) between SP Lower Range Value
(S1+44, S1+45) and SP Upper Range Value (S1+46, S1+47).
7. Set Point (SP) (S1+2, S1+3)
Sets the set point (SP) for PID control.
Set Point (SP) (S1+2, S1+3) is set as data type F (float) between SP Low Limit (S1+26, S1+27) and SP High Limit (S1+28, S1+29).
8. MV High Limit (S1+32, S1+33), MV Low Limit (S1+30, S1+31)
Sets the upper limit and lower limit of Output Manipulated Variable (MV) (S1+16, S1+17).
If the output manipulated variable calculated with PID control (0 to 100%) is greater than MV High Limit (S1+32, S1+33),
Output Manipulated Variable (MV) (S1+16, S1+17) will be MV High Limit. If the output manipulated variable calculated with PID
control (0 to 100%) is less than MV Low Limit (S1+30, S1+31), Output Manipulated Variable (MV) (S1+16, S1+17) will be MV
Low Limit.
MV High Limit (S1+32, S1+33) and MV Low Limit (S1+30, S1+31) are set as data type F (float) between 0.0 and 100.0 (0.0 and
100.0%).
19-30
Full Scale of
Set Point (SP)
FC6A S MICROS L
ERIES MART
SP Upper Range Value (S1+46, S1+47)
SP High Limit (S1+28, S1+29)
Set Point (SP) (S1+2, S1+3)
SP Low Limit (S1+26, S1+27)
SP Lower Range Value (S1+44, S1+45)
P M
ADDER ROGRAMMING ANUAL
FC9Y-B1726