Novus Line N320 User Manual download pdf

Line N320

Communication Protocol

Manual 5001292 V2.0

1. COMMUNICATION SERIAL

The optional serial interface RS485 allows to address up to 247 controllers in a network

communicating remotely with a host computer or master controller.

RS485 Interface

• Compatible line signals with RS485 standard

• 2 wire connection from master to up to 31 slaves indicators in a multidrop bus. It is

possible address 247 nodes with multiple outputs converters.

• Maximum communication distance: 1000 meters

• The RS485 signals are:

D1: Bidirectional data line.

D0: Bidirectional inverted data line.

C: Optional connection which left communication better.

General Characteristics

• Serial interface not isolated from input circuitry.

• Serial interface isolated from input circuitry, except in 24 V powered model.

• Baud rate: 9600

• Data Bits: 8

• Parity: None

• Stop Bits: 1

Communication Protocol

The MOSBUS RTU slave is implemented, available in most SCADA softwares in the

market.

All configurable parameters can be accessed (for reading or writing) through the

Registers Table. Broadcast commands are supported as well (address 0).

The available Modbus commands are:

03 - Read Holding Register

06 - Preset Single Register

The registers are arranged in a table in such a way that several registers can be read in

the same request.

1.1 CONFIGURATION OF SERIAL COMMUNICATION PARAMETERS

Two parameters must be configured in the device for serial communication:

addr

addraddr

addr

Device communication address. Each device must have an exclusive address.

1.2 REGISTERS TABLE

The Modbus registers hold the internal controller parameters. Each parameter is a 16-

bit word, with negative values represented as 2’s complement.

Holding

Registers

Parameter Description

0000 SP1

Read: OUTPUT1 Setpoint (control output).

Write: OUTPUT1 Setpoint (control output).

Range: from spl

splspl

spl to the value specified in spk

spkspk

spk.

Note: In the N320, this address also corresponds to the

Process Variable “PV” parameter.

0001 PV

Read: input temperature as measured by the sensor.

Write: not allowed.

Span: according to the sensor type used.

0002 IHM Status1

Read: IHM Status.

Write: not allowed.

Value format:

Bit 0 – OUT1 LED Bit 1 – OUT2 LED

Bit 10 – decimal Point Bit 12 – negative signal

0003 Control Status1

Read: measurement and OUTPUT1 status.

Write: not allowed.

Value format:

Bit 0 – Input Underflow Bit 1 –Input Overflow

Bit 8 – OUTPUT1 status Bit13 – defrost

0004 Value of the

parameter being

displayed

Read: Value of the parameter being presented on the display

Write: not allowed.

Max. Span: -199 to 999. The actual span depends on the

parameter being displayed.

0005 Firmware version

Parameter

sequence number

Read: controller firmware version & the sequential number that

identifies the parameter currently being displayed.

Write: not allowed.

Value format: XXYYh, where:

XX→Firmware version; YY→parameter number.

0006 Serial number

(High)

Read: first 3 digits of the serial number.

Write: not allowed.

Value format: XXXXh.

0007 Serial number

(Low)

Read: last 3 digits of the controller serial number.

Write: not allowed.

Value format: XXXXh.

0008 Hysteresis 1

Read: OUTPUT1 hysteresis.

Write: OUTPUT1 hysteresis.

Range: 0.1 a 50.0

0009 Control Status2

Read: OUTPUT2 Status.

Write: not allowed.

Value format:

Bit 0 – status de OUTPUT2

0010 SP2

Read: OUTPUT2 Setpoint.

Write: OUTPUT2 Setpoint.

Range: from spl

splspl

spl to the value specified in spk

spkspk

spk.

0011 Hysteresis 2

Read: OUTPUT2 hysteresis.

Write: OUTPUT2 hysteresis.

Range: 0.1 a 50.0.

0012 Offset

Read: Offset value

Write: Offset value

Range: -10.0 a 10.0

0013 Control Status3

Read: OUTPUT3 Status.

Write: not allowed.

Value format:

Bit 0 – status de OUTPUT3

0014 SP3

Read: OUTPUT3 Setpoint.

Write: OUTPUT3 Setpoint.

Range: from spl

splspl

spl to the value specified in spk

spkspk

spk.

0015 Hysteresis 3

Read: OUTPUT3 hysteresis.

Write: OUTPUT3 hysteresis.

Range: 0.1 a 50.0

Table 1 - Modbus registers table

Notes:

1- For the N320 model, the available registers are 0000 to 0007. In this model, both

registers 0000 and 0001 are assigned to the Process Variable value.

2- For the N321 model, the available registers are 0000 to 0008.

3- For the N322 model, the available registers are 0000 to 0012.

4- The N323 makes use of all registers (0000 to 0015).

5- The SP, PV and Hysteresis values are always multiplied by 10 to account for the

decimal point.

1.3 EXCEPTION RESPONSES – ERROR CONDITIONS

The MODBUS RTU protocol checks the CRC in the data blocks received.

Reception errors are detected by the CRC, causing the controller to discard the packet,

not sending any reply to the master.

After receiving an error-free packet, the controller processes the packet and verifies

whether the request is valid or not, sending back an exception error code in case of an

invalid request. Response frames containing error codes have the most significant bit of

the Modbus command set.

If a WRITE command sends an out-of-range value to a parameter, the controller will

clamp the value to the parameter range limits, replying with a value that reflects these

limits (maximum or minimum value allowed for the parameter).

The controller ignores broadcast READ commands; the controller processes only

broadcast WRITE commands.

Error Code Error Description

01 Invalid Command

02 Invalid Register Number or out of range

03 Invalid Register Quantity or out of range

Table 2 – Error code

1.4 ELECTRICAL CONNECTIONS

Figure 1 – Connections

Line N320 1

Summary of Contents

Page 1 - Line N320

Line N320 Communication Protocol Manual 5001292 V2.01. COMMUNICATION SERIAL The optional serial interface RS485 allows to address up to 247 controlle

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