NOVUS Controlador N960 - Manual (Page 4)

Controlador N960
NOVUS AUTOMATION 4/4
ALARM FUNCTION DESCRIPTION
Minimum and maximum alarms are used to signal extreme
temperature values. Such extreme values are defined in the “aisp”
and “a2sp”. Differential alarms are used to signal deviations between
the temperature and the control setpoint (SP). User-defined values in
the “aisp” and “a2sp” parameters represent the values of such
deviations.
The initial blocking prevents the alarm from being triggered when the
controller is turned on until the temperature reaches the SP value for
the first time.
The error alarm in the sensor signals sensor faults.
Table 2 shows the operation of each alarm function, using alarm 1 as
an example, and presents its identification code in the “aifv” and
“a2fv” parameters.
TYPE PROMPT ACTION
Disabled Off Alarm disabled
Open Sensor
(input Error)
Ierr
Triggered when the sensor is
broken
Minimum
value
(Low)
Lo
A1SP
PV
OFF ON
Maximum
value (High)
Ki
A1SP
PV
Minimum
differential
(Differential
Low)
Dif.lo PV
SP SP – A1SP
Maximum
differential
(Differential
High)
Dif.ki PV
SP + A1SP SP
Out of range
differential
(Differential
Out)
Dif.ov PV
SP + A1SP SP SP – A1SP
Differential
within range
(Differential
In)
Dif.In PV
SP + A1SP SP SP – A1SP
Table 2 – Alarm functions and identification codes
PID PARAMETERS AUTO-TUNE
One of the major doubts users have is to know which values to adopt
in PID parameters for a more effective control of the process. The
Auto-tune (Atvn) is the controller resource that determines such
values automatically.
When the Auto-tune is enabled, the controller will control the process
temperature and identify its characteristics, calculating the best
values for the PID parameters. During auto-tune the process is
controlled in the ON/OFF mode in the programmed value of the
setpoint. Depending on the process features, great temperature
oscillations may occur, above and below the SP value. The user must
check if the process supports such oscillations. Auto-tune can take
several minutes to conclude in some processes.
In the controller front panel, the signal TUNE lights when auto-tuning
is being performed. At the end of the process, the signal disappears.
For other SP values, other PID parameters may be required. The
recommended procedure is the following:
Program SP as a value close to the value in which the process will
operate after tuned.
Enable the auto-tune in the “atvn” prompt by selecting 1.
Program 1 in the “rvn” prompt.
If auto-tune does not result a satisfactory control, Table 3 shows
actions that will adjust the process behavior.
PARAMETER PROBLEM SOLUTION
Proportional band
Slow response Decrease
Large oscillation Increase
Integration rate
Slow response Increase
Large oscillation Decrease
Derivative time
Slow response or
instability
Decrease
Large oscillation Increase
Table 3 – Orientation for the manual adjustment of the PID parameters
SAFETY INFORMATION
This product is not a protection or safety device and its alarms are not
intended to protect against product failures. Independent safety devices
should be always provided if personnel or property are at risk.
Product performance and specifications may be affected by its
environment and installation. It’s user’s responsibility to assure
proper grounding, shielding, cable routing and electrical noise
filtering, in accordance with local regulations, EMC standards and
good installation practices.
SUPPORT AND MAINTENANCE
This product contains no serviceable parts inside. Contact our local
distributor in case you need authorized service. For troubleshooting,
visit our FAQ at www.novusautomation.com.
LIMITED WARRANTY AND LIMITATION OF
LIABILITY
NOVUS warrants to the original purchaser that this product is free
from defects in material and workmanship under normal use and
service within one (1) year from the date of shipment from factory or
from its official sales channel to the original purchaser.
NOVUS liability under this warranty shall not in any case exceed the
cost of correcting defects in the product or of supplying replacement
product as herein provided and upon the expiration of the warranty
period all such liability shall terminate.
For complete information on warranty and liability limitations, check
appropriate section in our web site: www.novusautomation.com.