Special recommendations, Calibration, Input calibration – NOVUS N1500FT Indicator User Manual

Page 8: Output calibration, Serial communication, Features, Electrical connections: rs485 interface, Configuration of serial communication parameters

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N1500FT Flow Indicator

NOVUS AUTOMATION

8/9

MESSAGE

PROBLEM DESCRIPTION

VVVVV

Value reading is above limits allowed for this

sensor or signal.

nnnnn

Value reading is below limits allowed for this

sensor or signal.

------

Open input. No sensor or signal.
Also displayed in the “feeder” screens in case

no alarm is configured as “feeder”.

SPECIAL RECOMMENDATIONS
Should your indicator be repaired, special care must be taken with

handling. The device must be removed from the case and immediately

placed in an antistatic wrap, protected from extreme heat and humidity.

CALIBRATION

Both analog input and output are factory calibrated, and recalibration

should not be performed by inexperienced operators. If recalibration

of a given range is necessary, proceed as follows.
INPUT CALIBRATION
1.
Set input type to be calibrated to 4-20 mA;
2. Program inll (lower limit) and inkl (higher limit) indication

parameters to maximum and minimum values of input type;

3. Apply to entry a signal corresponding to a known indication and

close to its lower limit;

4. Enter calibration cycle with correct password;
5. Access inl( parameter. With

and

keys, have

parameter display show applied value. Then Press

;

6. Apply to entry a signal corresponding to a known indication and

close to its higher limit;

7. Access ink( parameter. With

and

keys, have

parameter display show applied value;

8. Press

or

to exit screen and activate calibration.

OUTPUT CALIBRATION
1.
Mount a milliammeter in the analog control output;
2. Enter calibration cycle with correct password;
3. Select oUL( parameter. Use

and

keys so that the

device recognizes the process of calibration of current output.

4. Read current in the milliammeter and enter it in the oUL(

parameter using

and

keys. Then press

;

5. In parameter oUx(, use

and

keys so that the device

recognizes the process of calibration of current output;

6. Read current in the milliammeter and enter it in the oUx(

parameter using

and

keys;

7. Press

or

to exit screen and activate calibration.

SERIAL COMMUNICATION

The indicator may be optionally supplied with a RS485 asynchronous

serial communication interface for communicating with a supervisor

computer (master). The indicator always operates as slave.
Communication is always initiated by the master, which sends a

request to the slave address with which it wants to communicate. The

addressed slave takes control and sends a response to the master.
The indicator takes broadcast type commands (addresses to all

network instruments). For this type of command, the indicator does

not send any reply or acknowledgement.

FEATURES
Signals compatible with RS485 standard. MODBUS (RTU) Protocol.

2-wire connection between 1 master and up to 31 indicators (it is

possible to address up to 247 units) in bus topology.

Communication signals are electrically isolated from the rest of the

indicator.
• Maximum connection distance: 1000 meters.
• Selectable speed; 8 bits of data; 1 stop bit; selectable parity (no

parity, even or odd).

• Start time of response transmission: 100 ms maximum after

receiving the command.

ELECTRICAL CONNECTIONS: RS485 INTERFACE
RS485 signals are:

D1

D

D+

B

Bi-directional data line

Terminal 25

D0

D-

A

Reverse bi-directional data

line

Terminal 26

C

Optional connection that

improves communication

performance.

Terminal 27

GND

CONFIGURATION OF SERIAL COMMUNICATION PARAMETERS
Two parameters must be configured for serial use:
Baud

: Communication speed.

Prty

: Communication parity.

Addr

: Communication address of indicator.

REDUCED REGISTERS TABLE FOR

SERIAL COMMUNICATION

Communication Protocol
Slave MODBUS RTU protocol supported. All configurable

parameters of the indicator may be read and/or written through serial

communication. Writing on registers in broadcast mode using the

address 0 is also allowed.
The following Modbus commands are available:

03 - Read Holding Register

06 - Preset Single Register

05 - Force Single Coil

16 - Preset Multiple Register

Holding Registers Table
The following are the most commonly used registers. For further

information, refer to the Table of Registers for Serial

Communication available for download on the flow indicator

webpage at

www.novusautomation.com

.

The registers below are read-only. The ones that are available in a

floating point format require two registers for being 32-bit values.

Address Parameter

Register Description

0000

and

0001

Instantaneous

flow rate

Instantaneous flow value in floating

point (IEEE-754).

0002

and

0003

Totalized Flow Flow totalization value in floating

point (IEEE-754).

0004

and

0005

Non-resettable

Totalized Flow

Grand total flow value in floating point

(IEEE-754).

0013

to

0016

Totalized Flow

Flow totalization value in integer

format (with signal) of 64 bits. The

most significant part is in the first

register.

0017

to

0020

Non-resettable

Totalized Flow

Grand total flow value in integer

format (with signal) of 64 bits. The

most significant part is in the first

register.

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