Serial communication, Registers – NOVUS FieldLogger Register User Manual

Page 5

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FieldLogger Register

NOVUS AUTOMATION

5/8

SERIAL COMMUNICATION

The logger has a master-slave asynchronous serial communication
interface RS485 to communicate with a supervisory computer
(master). The logger is always the slave.

Communication always start with the master, which sends a
command to the slave address with whom it wants to communicate.
The addressed slave undertakes the command and sends the
corresponding answer to the master.

The logger also accepts broadcast commands.

Note: Recommended cables for serial communication are 3 x 24
AWG + shield. This way the shield can be grounded while cables are
used for signals.

FEATURES

Signals supported by RS485 standard. We recommend reading the
document “Basic concepts of RS485 and RS422” available in the CD
that is delivered with the equipment.

Communication signals are electrically isolated from the rest of the
device, with configurable speed of 1200, 2400, 4800, 9600, 19200
and 57600 bps.

Number of data bits: 8.

Parity: none, odd or even.

Number of stop bits: 1 (odd or even parity) or 2 (no parity).

Response delay: up to 20 ms after command is received.

Protocol: Modbus RTU, available in most supervisory software of the
industry.

RS-485 signals are:

D1 D D+ B Bidirectional data line

Terminal 17

D0

D:

D- A Reversed bidirectional data

line

Terminal 18

C

GND

Optional connection that
enhances

the

communication performance

Terminal 16

PHYSICAL SPECIFICATIONS

Three-wire connection (2 data wires and 1 common) between 1
master and up to 247 instruments (maximum of 31 per network
segment) in bus topology.

Shielded cable, 3 x 24 AWG, with shield grounded in one end;

16 pF capacitance at every 30 m;

Typical impedance: 120 Ohms;

Maximum length 1200 m;

REGISTERS

The logger configurable parameters are organized in a Table of
Registers. The block reading command makes possible to read
multiple registers with the same request.

The configuration software, however, makes such table not
necessary, once it reads and writes in all registers that require
configuration. Each parameter in the table is a word of 16 bits.

The available Modbus command for the reading operation is the
following:

03 - Read Holding Register

This way, it is worth reporting the following registers, which are
equivalent to the holding registers (reference 4X):

HOLDING

REGISTERS

DESCRIPTION

0000

Current value of channel 1

0001

Current value of channel 2

0002

Current value of channel 3

0003

Current value of channel 4

0004

Current value of channel 5

0005

Current value of channel 6

0006

Current value of channel 7

0007

Current value of channel 8

0008

Informs alarm status

0009

Reserved: Informs general status

0010

Informs channels 1 and 2 status

0011

Informs channels 3 and 4 status

0012

Informs channels 5 and 6 status

0013

Informs channels 7 and 8 status

0014

Current time (seconds and minute)

0015

Current time (hour and day)

0016

Current time (month and year)

0017

Channel 1 configuration

0018

Channel 2 configuration

0019

Channel 3 configuration

0020

Channel 4 configuration

0021

Channel 5 configuration

0022

Channel 6 configuration

0023

Channel 7 configuration

0024

Channel 8 configuration

0076

Bytes 0 and 1 of the title string

0077

Bytes 2 and 3 of the title string

0078

Bytes 4 and 5 of the title string

0079

Bytes 6 and 7 of the title string

0080

Bytes 8 and 9 of the title string

0081

Bytes 10 and 11 of the title string

0082

Bytes 12 and 13 of the title string

0083

Bytes 14 and 15 of the title string

0084

Bytes 0 and 1 of channel 1 string (tag)

0085

Bytes 2 and 3 of channel 1 string (tag)

0086

Bytes 4 and 5 of channel 1 string (tag)

0087

Bytes 6 and 7 of channel 1 string (tag)

0088

Bytes 0 and 1 of channel 2 string (tag)

0089

Bytes 2 and 3 of channel 2 string (tag)

0090

Bytes 4 and 5 of channel 2 string (tag)

0091

Bytes 6 and 7 of channel 2 string (tag)

0092

Bytes 0 and 1 of channel 3 string (tag)

0093

Bytes 2 and 3 of channel 3 string (tag)

0094

Bytes 4 and 5 of channel 3 string (tag)

0095

Bytes 6 and 7 of channel 3 string (tag)

0096

Bytes 0 and 1 of channel 4 string (tag)

0097

Bytes 2 and 3 of channel 4 string (tag)

0098

Bytes 4 and 5 of channel 4 string (tag)

0099

Bytes 6 and 7 of channel 4 string (tag)

0100

Bytes 0 and 1 of channel 5 string (tag)

0101

Bytes 2 and 3 of channel 5 string (tag)

0102

Bytes 4 and 5 of channel 5 string (tag)

0103

Bytes 6 and 7 of channel 5 string (tag)

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