Mitsubishi Electric MELSEC-Q/L - PID Control

7 APPLICATION INSTRUCTIONS
7.18 PID Instruction
729
7
PID control
PID
Processing details
• When the program is run with the set value (S1), process value (S2), and parameters ((S3) to (S3)+6) set, the manipulated
value (MV) is stored in the output value (D) every sampling time (S3).
• The setting items of arguments are listed below.
*1 When auto tuning is not used, the same number of points as that used when the step response method is used is occupied.
• QnUDVCPU, LCPU: The serial number (first five digits) is "16112" or later.
(S1): Device number where the set value (SV) is stored (device name)
(S2): Device number where the process value (PV) is stored (device name)
(S3): Start number of devices where parameters are stored (device name)
(D): Device number where the manipulated value (MV) is stored (device name)
Setting
data
Internal device R, ZR J\ U\G Zn Constant Others
Bit Word Bit Word
(S1) 
(S2) 
(S3) 
(D) 
Setting item Description Setting range
(S1) Set value (SV) Set the set value (SV). However, when the limit cycle method is used, the set values for
auto tuning and PID control may be different. In this case, a value obtained by adding a
bias value is set for the time being and, when the auto tuning flag turns OFF, the actual
set value needs to be stored.
1 point
(S2) Process value (PV) Set the input value for PID operation. 1 point
(S3) Parameters
*1
• When the limit cycle method is used
Devices of 29 points from the start device specified in (S3) are occupied.
• When the step response method is used
When none of bits 1, 2, and 5 of the action setting (ACT) is "0", devices of 25 points from
the start device specified in (S3) are occupied.
When all of bits 1, 2, and 5 of the action setting (ACT) are "0", devices of 20 points from
the start device specified in (S3) are occupied.
See the left.
(D) Manipulated value
(MV)
• When normal processing is performed
The user sets the initial output value before driving the instruction. After the instruction is
driven, the operation result is stored.
• When the limit cycle method is used
The ULV or LLV value is automatically output during auto tuning, and the given MV value
is set after the end of auto tuning.
• When the step response method is used
The user sets the step output value before driving the instruction. The MV output cannot
be changed by the PID instruction during auto tuning.
1 point
Basic
High
performance
Process Redundant Universal
Ver.
LCPU
Ver.
PID
PID
S1
S2
S3
D
Command
PID
S1 S2 S3
D
Command input