background image

N1020 Temperature Controller 

NOVUS AUTOMATION 

6/8 

DETERMINATION OF PID PARAMETERS 

The determination (or tuning) of the PID control parameters in the 

controller can be carried out in an automatic way and auto-adaptative 

mode. The automatic tuning is always initiated under request of the 

operator, while the auto-adaptive tuning is initiated by the controller 

itself whenever the control performance becomes poor. 
Automatic  Tuning:  In the beginning of the automatic tuning  the 

controller has the same behavior of an ON/OFF controller, applying 

minimum and maximum performance to the process. Along the 

tuning process the controller's performance is refined until its 

conclusion, already under optimized PID control. It begins 

immediately after the selection of the options FAST, FULL, RSLF or 

TGHT, defined by the operator in the parameter ATUN. 
Auto-adaptative Tuning: Is initiated by the controller whenever the 

control performance is worse than the one found after the previous 

tuning. In order to activate the performance supervision and auto-

adaptative tuning, the parameter ATUN must be adjusted for SELF, 

RSLF or TGHT. The controller's behavior during the auto-adaptative 

tuning will depend on the worsening of the present performance. If 

the maladjustment is small, the tuning is practically imperceptible for 

the user. If the maladjustment is big, the auto-adaptive tuning  is 

similar to the method of automatic tuning, applying minimum and 

maximum performance to the process in ON/OFF control. 

 

Fig. 04 – Example of auto tuning 

 

Fig. 05 – Example of auto-adaptative tuning 

The operator main select through the ATUN parameter, the desired 

tuning type among the following options: 

 

OFF

: The controller does not carry through automatic tuning or 

auto-adaptative tuning. The  PID  parameters  will  not  be 

automatically determined nor optimized by the controller. 

 

FAST

: The controller will  the process automatic  tuning  one 

single time, returning to the OFF mode after finishing. The tuning 

in this mode is completed in less time, but not as precise as in 

the FULL mode. 

 

FULL

: The same as the  FAST  mode, but  the  tuning  is  more 

precise and slower, resulting in better performance of the P.I.D. 

 

SELF

:  The  performance  of the process is monitored  and  the 

auto-adaptative tuning  is automatically initiated by the 

controller whenever the performance poorer. 
After a tuning level, the controller starts collecting data from the 

process for determining the performance benchmark that will 

allow evaluate the need for future tunings. This phase is 

proportional to the process response time and is signaled by the 

flashing TUNE indication on the display. It is recommended not 

to turn the controller off neither change the SP during this 

learning period. 
It is recommended not to turn the controller off neither change the 

SP during this learning period. 

 

rSLF

: Accomplishes the automatic tuning and returns into the 

SELF  mode. Typically  used  to force an immediate  automatic 

tuning  of a controller  that was  operating  in  the  SELF  mode, 

returning to this mode at the end. 

 

TGHT

: Similar to the SELF mode, but in addition auto-adaptative 

tuning,  it also executes the  automatic  tuning  whenever  the 

controller is set in RUN=YES or when the controller is turned on. 

Whenever the parameter ATUN is altered by the operator into a 

value different from OFF, an automatic tuning is immediately 

initiated by the controller (if the controller is not in RUN=YES, the 

tuning will begin when it passes into this condition). The 

accomplishment of this automatic tuning is essential for the correct 

operation of the auto-adaptative tuning. 
The methods of automatic tuning and auto-adaptative tuning are 

appropriate for most of the industrial processes. However, there may 

be processes or even specific situations where the methods are not 

capable to determine the controller's parameters in a satisfactory 

way, resulting in undesired oscillations or even taking the process to 

extreme conditions. The oscillations themselves imposed by the 

tuning methods may be intolerable for certain processes.  
These possible undesirable effects must be considered before 

beginning the controller's use, and preventive measures must be 

adopted in order to assure the integrity of the process and users. 
The AT signaling device will stay on during the tuning process.  
In the case of PWM or pulse output, the quality of tuning will also 

depend on the level time adjusted previously by the user. 
If the tuning does not result in a satisfactory control, refer to Table 05 

for guidelines on how to correct the behavior of the process. 

PARAMETER 

VERIFIED PROBLEM 

SOLUTION 

Proportional Band 

Slow answer 

Decrease 

Great oscillation 

Increase 

Rate of Integration 

Slow answer 

Increase 

Great oscillation 

Decrease 

Derivative Time 

Slow answer or instability 

Decrease 

Great oscillation 

Increase 

Table 05 - Guidance for manual adjustment of the PID parameters 

MAINTENANCE 

PROBLEMS WITH THE CONTROLLER 
Connection errors and inadequate programming are the most 

common errors found during the controller operation. A final revision 

may avoid loss of time and damages. 
The controller displays some messages to help the user identify 

problems. 

MESSAGE 

DESCRIPTION OF THE PROBLEM 

----

 

Open input. No sensor o signal.   

Err1

 

Err6

 

Connection and/or configuration errors. Check the wiring 

and the configuration. 

Other error messages may indicate hardware problems requiring 

maintenance service.

 

 

 

 

 

 

 

 

Summary of Contents for N1020

Page 1: ...nsult the DEVICE MANAGER in the Windows CONTROL PANEL to identify the COM port that was assigned to the controller Consult the mapping of the MODBUS memory in the controller s communications manual an...

Page 2: ...the value of measured PV is above the value defined for alarm Setpoint SPA1 PV dif Alarm of Differential Value In this function the parameters SPA1 and SPA2 represent the deviation of PV in relation...

Page 3: ...ine trimming the PV indication to compensate for sensor errors Default value zero SERIAL COMMUNICATION For full documentation download the Registers Table N1020 for Serial Communication on our web sit...

Page 4: ...opriate for cooling Turns control output on when PV is above SP sfst Softstart SoftStart Function Time in seconds during which the controller limits the MV value progressively from 0 to 100 It is enab...

Page 5: ...fications carried out by the user ovll Output Low Limit Lower limit for the control output Minimum percentage value assumed by the control output when in automatic mode and in PID Typically configured...

Page 6: ...E indication on the display It is recommended not to turn the controller off neither change the SP during this learning period It is recommended not to turn the controller off neither change the SP du...

Page 7: ...tion with a Pt100 simulator pay attention to the simulator minimum excitation current requirement which may not be compatible with the 0 170 mA excitation current provided by the controller N1020 PARA...

Page 8: ...PR OUT1 Pulse OUT2 Relay B Digital Communication 485 Interface communication RS485 C Power Supply Nothing shown 100 240 Vac 48 240 Vdc 50 60 Hz 24V 12 24 Vdc 24 Vac SAFETY INFORMATION Any control sys...

Reviews: