Novus N1050, Instruction Manual

Page: 7 / 8

N1050 Controller
NOVUS AUTOMATION 7/8
If the tuning does not result in a satisfactory control, refer to Table 04
for guidelines on how to correct the behavior of the process.
PARAMETER VERIFIED PROBLEM SOLUTION
Band Proportional
Slow answer Decrease
Great oscillation Increase
Rate Integration
Slow answer Increase
Great oscillation Decrease
Derivative Time
Slow answer or instability Decrease
Great oscillation Increase
Table 04 - Guidance for manual adjustment of the PID parameters
For further details on PID tuning, visit our web site
www.novusautomation.com .
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 or signal.
Erro
Connection and/or configuration problems.
Check the wiring and the configuration.
Other error messages may indicate hardware problems requiring
maintenance service.
CALIBRATION OF THE INPUT
All inputs are factory calibrated and recalibration should only be done
by qualified personnel. If you are not familiar with these procedures
do not attempt to calibrate this instrument.
The calibration steps are:
a) Configure the input type to be calibrated in the
type
parameter.
b) Configure the lower and upper limits of indication for the maximum
span of the selected input type.
c) Go to the Calibration Cycle.
d) Enter the access password.
e) Enable calibration by setting
YES
in
CaLb
parameter.
f) Using an electrical signals simulator, apply a signal a little higher
than the low indication limit for the selected input.
g) Access the parameter
in.LC
. With the keys and adjust
the display reading such as to match the applied signal. Then
press the key.
h) Apply a signal that corresponds to a value a little lower than the
upper limit of indication.
i) Access the parameter
in.HC
. With the keys and adjust
the display reading such as to match the applied signal.
j) Return to the Operation Cycle.
k) Check the resulting accuracy. If not good enough, repeat the
procedure.
Note : When checking the controller calibration 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.
SERIAL COMMUNICATION
The controller can be supplied with an asynchronous RS-485 digital
communication interface for master-slave connection to a host
computer (master).
The controller works as a slave only and all commands are started by
the computer which sends a request to the slave address. The
addressed unit sends back the requested reply.
Broadcast commands (addressed to all indicator units in a multidrop
network) are accepted but no reply is sent back in this case.
CHARACTERISTICS
• Signals compatible with RS-485 standard. MODBUS (RTU)
Protocol. Two wire connection between 1 master and up to 31
(addressing up to 247 possible) instruments in bus topology. The
communication signals are electrically insulated from the rest of
the device;
•
Maximum connection distance: 1000 meters.
• Time of disconnection for the controller: Maximum 2 ms after last
byte .
• Selectable speed; 8 data bits; 1 stop bit; selectable parity (no
parity, pair or odd);
•
Time at the beginning of response transmission: maximum 100 ms
after receiving the command.
The RS-485 signals are:
D1 D D + B Bi-directional data line. Terminal 15
D0 D - A
Bi-directional inverted data line. Terminal 16
C
Optional connection that improves the
performance of the communication.
Terminal 17
GND
CONFIGURATION OF PARAMETERS FOR SERIAL COMMUNICATION
Three parameters must be configured for using the serial type:
baud
: Communication speed.
prty
: Parity of the communication.
addr
: Communication address for the controller..
REDUCED REGISTERS TABLE FOR SERIAL
COMMUNICATION
Communication Protocol
The MOSBUS RTU slave is implemented. All configurable
parameters can be accessed for reading or writing through the
communication port. Broadcast commands are supported as well
(address 0).
The available Modbus commands are:
03 - Read Holding Register 06 - Write Single Register
05 - Write Single Coil 16 - Write Multiple Register
Follows a description of the usual communication registers. For full
documentation download the Registers Table for Serial
Communication in the N1200 section of our website
www.novusautomation.com .
All registers are 16 bit signed integers.
Address Parameter Register Description
0000 Active SP Read: Active control SP (main SP, from
ramp and soak or from remote SP).
Write: to main SP.
Range: from
sp.LL
to
sp.HL
.
0001 PV Read: Process Variable.
Write: Not allowed.
Range: Minimum value is the one
configured in
sp.LL
and the maximum
value is the one configured in
sp.HL
.
Decimal point position depends on
dp.po
value.
In case of temperature reading, the value
read is always multiplied by 10,
independently of
dp.po
value.
D: