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

• If hunting continues too long, increase ProportionalBand or increase IntegrationTime.
PV
SP
Increase ProportionalBand or increase IntegrationTime.
• If rapid hunting occurs, decrease DerivativeTime.
PV
SP
Decrease DerivativeTime.
Initial PID Constants for Temperature Control
If you use the PIDAT instruction for temperature control, use the following initial values of the PID con-
stants as reference. Use the default values for the other variables.
Variables
ProportinalBand
IntegrationTime
DerivativeTime
* If you perform autotuning, use the results from autotuning.
Precautions for Correct Use
• The values of PV and SP must be between the values of RngLowLmt and RngUpLmt, inclusive. Align
the units of these variables as shown below.
Unit
PV = (Process value in physical units − MIN)/(MAX − MIN) × 100
% FS
SP = (Set point in physical units − MIN)/(MAX − MIN) × 100*
Physi- PV = Process value in physical units
cal unit
SV = Set point in physical units
* MAX: Upper limit of input range in physical units, MIN: Lower limit of input range in physical units,
• The following table shows which variables can be changed depending on the operating status.
Variables
Run
ManCtl
StartAT
PV
SP
MVLowLmt
MVUpLmt
ManResetVal
MVTrackSw

NJ-series Instructions Reference Manual (W502)

Time
Time
Initial values (reference values)*
10%FS
233 s
40 s
Values of PV and SP
Instruction execution
*1
stopped
Possible
Possible
Possible
Possible
Possible
Possible
Possible
Possible
Possible
2 Instruction Descriptions
Values of RngLowLmt and
RngLowLmt = 0
RngUpLmt = 100
RngLowLmt = MIN
RngUpLmt = MAX*
Control status
Automatic operation
when autotuning is not
*2
being executed
Possible
Possible
Possible
Possible
Possible
Possible
Possible
Possible
Possible
RngUpLmt
Automatic operation
when autotuning is being
*3
executed
Possible
Possible
Possible
Possible
Not possible
Not possible
Not possible
Not possible
Not possible
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2