Nj-Series Instructions Reference Manual (W502 - Omron NJ501-1500 Reference Manual

2 Instruction Descriptions
Set point filter
1 + (1−α)Ti ⋅ s
+
Set
1 + Ti ⋅ s
−
point
Starting PID Control
You must use suitable PID constants to execute this instruction. There are the following two ways to
achieve this.
When Suitable PID Constants Are Not Known
Perform autotuning at the start of operation to find suitable PID constants. Change the value of Run
to TRUE while the value of StartAT is TRUE. First, autotuning is executed, and then PID control is
started with the PID constants that are found.
When Suitable PID Constants Are Known
Set suitable PID constants in ProportinalBand, IntegrationTime, and DerivativeTime, and then
change Run to TRUE. ProportinalBand, IntegrationTime, and DerivativeTime are in-out variables.
You cannot set constants for the input parameters. Always define suitable variables, and then assign
the values to input parameters.
You can change the PID constants during operation. You can also perform autotuning during opera-
tion. To start autotuning during operation, change the value of StartAT to TRUE.
Control Status and Manipulated Variable
Manipulated variable MV is determined according to the control status as shown in the following table.
Control status
Error end
MV tracking dur-
ing automatic
operation
Autotuning dur-
ing automatic
operation
Not autotuning
during automatic
operation
Instruction exe-
cution stopped
Manual opera-
tion
2-404
Proportional +
integral components
Manipulated
Deviation
Kp variable
+
Kp +
Ti ⋅ s −
Advanced derivative
component
Kp ⋅ Td ⋅ s
1 + λ ⋅ Td ⋅ s
Value of variable
ManCtl
Run (exe-
(man-
cution con-
ual/auto
dition)
control)
TRUE
FALSE
FALSE
TRUE ---
Disturbance
+
Process value
Controlled
system
+
Man-
TrackSw
Error (error
(manual
end)
tracking
switch)
TRUE ---
TRUE
FALSE
FALSE
--- ---

NJ-series Instructions Reference Manual (W502)

Kp: Proportional constant
Ti: Integration time
Td: Derivative time
s: Laplace operator
α: 2-PID parameter
λ: Incomplete derivative coefficient
Manipulated vari-
ATBusy
able MV
(autotun-
ing busy)
ErrorMV (error MV)
MVTrackVal (MV
FALSE
tracking value)
TRUE Value repeatedly
changes between
upper limit of MV
and lower limit of
MV.
FALSE Value calculated
with current PID
constants.
StopMV (Stop MV)
ManMV (manual
manipulated vari-
able)