NOVUS NC400-6 - Manual

NC400-6
Communication Protocol
1. SERIAL COMMUNICATION
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 Communication common signal. Interconnect this terminal in all devices of the
bus for protection (optional).
General Characteristics
• Optically isolated serial interface
•
Baud rate: 9600 bps.
•
Data bits: 8
• Parity: None
•
Stop Bits: 1
Communication Protocol
The MOSBUS RTU slave is implemented, available in most SCADA softwares in the
market.
The available Modbus commands are:
03 - Read Holding Register
16 - Write Multiple Registers
Each “03” (Read Holding Register) and “16” (Write Multiple Registers) command can
accept the reading/writing of up to 4 registers.
1.1 CONFIGURATION OF NC400-6
NC400-6 devices with RS485 serial communication interface will have the Addr Addr Addr Addres es es es
parameter in its Hardware Configuration cycle. This parameter must be set with the
Modbus address of the device on the communication bus. Each device must have a
unique address. Valid addresses must be between 1 and 247.
addr addr addr addres es es es Device communication address. Each device must have a unique
address.
1.2 REGISTERS TABLE
Registers are internal parameters of the device. Each parameter of the table is a 16 bit
signed (two’s complement) word.
Holding
Registers
Parameter Register Description
0000 Main Counter
(HIGH)
Read: Main Counter, most significant word
Write: Not allowed.
Format: Floating Point (IEEE-754)
0001 Main Counter
(LOW)
Read: Main Counter, less significant word
Write: Not allowed.
Format: Floating Point (IEEE-754)
0002 Batch Counter
(HIGH)
Read: Batch Counter, most significant word
Write: Not allowed.
Format: Floating Point (IEEE-754)
0003 Batch Counter
(LOW)
Read: Batch Counter, less significant word
Write: Not allowed.
Format: Floating Point (IEEE-754)
0004 Totalizer
Counter
(HIGH)
Read: Totalizer Counter, most significant word
Write: Not allowed.
Format: Floating Point (IEEE-754)
0005 Totalizer
Counter
(LOW)
Read: Totalizer Counter, less significant word
Write: Not allowed.
Format: Floating Point (IEEE-754)
0006 Set point 1
Main Counter
(HIGH)
Read: Set point 1 for the Main Counter, most significant word
Write: Set point 1 for the Main Counter, most significant word
Format: Floating Point (IEEE-754)
0007 Set point 1
Main Counter
(LOW)
Read: Set point 1 for the Main Counter, less significant word
Write: Set point 1 for the Main Counter, less significant word
Format: Floating Point (IEEE-754)
0008 Set point 2
Main Counter
(HIGH)
Read: Set point 2 for the Main Counter, most significant word
Write: Set point 2 for the Main Counter, most significant word
Format: Floating Point (IEEE-754)
0009 Set point 2
Main Counter
(LOW)
Read: Set point 2 for the Main Counter, less significant word
Write: Set point 2 for the Main Counter, less significant word
Format: Floating Point (IEEE-754)
0010 Set point
Batch Counter
(HIGH)
Read: Set point for the Batch Counter, most significant word
Write: Set point for the Batch Counter, most significant word
Format: Floating Point (IEEE-754)
0011 Set point
Batch Counter
(LOW)
Read: Set point for the Batch Counter, less significant word
Write: Set point for the Batch Counter, less significant word
Format: Floating Point (IEEE-754)
0012 Set point
Totalizer
Counter (HIGH)
Read: Set point for the Totalizer Counter, most significant word
Write: Set point for the Totalizer Counter, most significant word
Format: Floating Point (IEEE-754)
0013 Set point
Totalizer
Counter (LOW)
Read: Set point for the Totalizer Counter, less significant word
Write: Set point for the Totalizer Counter, less significant word
Format: Floating Point (IEEE-754)
0014 Status Read: Output Status, Overflow, MAX and MIN.
Write: Not allowed.
Format: Binary
Bit - Function
0 - OUT1
1 - OUT2
2 - MAX (Main Counter)
3 - MAX (Batch Counter)
4 - MAX (Totalizer Counter)
5 - MIN (Main Counter)
6 - MIN (Batch Counter)
7 - MIN (Totalizer Counter)
8 - HOLD
9 - Overflow (Main Counter)
10 - Overflow (Batch Counter)
11 - Overflow (Totalizer Counter)
0015 Serial Number
(HIGH)
Read: Device serial number, most significant word
Write: Not allowed.
Format: Decimal
0016 Serial Number
(LOW)
Read: Device serial number, less significant word
Write: Not allowed.
Format: Decimal
Table 1 - Registers table
Note:
The Floating Point coding format used follows the standard IEEE-754 in mode
HIGH:LOW.
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 device 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, no write is done (the
parameter keeps the value it had before the command) and an Error Code 03 is
returned as a response.
The controller ignores broadcast READ commands; the controller processes only
broadcast WRITE commands.
Error Code Error Description
01 Invalid Command or noninexistent
02 Invalid Register Number or out of range
03 Invalid Register Quantity or out of range
Table 2 - Exception response error codes