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Compalarm C2C protocol communication instruction manual IM163-U v0.5 pag. 1 / 8

INSTRUCTION MANUAL IM163-U v0.5

COMPALARM C2C MODBUS-RTU COMMUNICATION PROTOCOL

MODBUS PROTOCOL Modbus is a master-slave communication protocol able to support up to 247 slaves organized as a bus or as a star network. The physical link layer can be RS232 for a point to point connection or RS485 for a network. The communication is half-duplex. The network messages can be Query-Response or Broadcast type. The Query-Response command is transmitted from the Master to an established Slave and generally it is followed by an answering message. The Broadcast command is transmitted from the Master to all Slaves and is never followed by an answer. MODBUS use two modes for transmission. A) ASCII Mode: uses a limited character set as a whole for the communication. B) RTU Mode: binary, with time frame synchronization, faster than the ASCII Mode, uses half so long data block than

the ASCII Mode. GENERIC MESSAGE STRUCTURE:

START OF

FRAME

ADDRESS FIELD

FUNCTION CODE

DATA FIELD

ERRORCHECK

END OF

FRAME

START OF FRAME = Starting message marker ADDRESS FIELD = Includes device address in which you need to communicate in Query-Response mode. In case

the message is a Broadcast type it includes 00. FUNCTION CODE = Includes the operation code that you need to perform. DATA FIELD = Includes the data field. ERROR CHECK = Field for the error correction code. END OF FRAME = End message marker. Mode RTU communication frame structure: START OF FRAME = silence on line for time >=4 characters ADDRES FIELD = 1 character FUNCTION CODE = 1 character DATA FIELD = N characters ERROR CHECK = 16 bit CRC END OF FRAME = silence on line for time >=4 characters Wait time for response :

- typical : 150 ms - worst case : 300 ms.


READING OF THE REGISTERS ( Function Code $ 03) Reads the binary contents of holding registers (2X references) in the slave. Broadcast is not supported. The Query message specified the starting register and quantity of register to be read. QUERY:

START OF

FRAME

ADDRESS FIELD

FUNCTION CODE

START ADDRESS

No. OF REGISTERS

ERRORCHECK

END OF

FRAME

START OF FRAME = Starting message marker. ADDRESS FIELD = Device address (01...F7 HEX) (1 byte). FUNCTION CODE = Operation code (03 HEX) (1 byte). START ADDRESS = First register address to be read (2 byte). No. OF REGISTERS = Number of registers to be read ERROR CHECK = Check sum. END OF FRAME = End message marker. WARNING: It is possible to read more than one variable at the same time (max 16) only if their addresses are consecutive and the variables on the same line cannot be divided. For each register, the first byte contains the high order bits and the second contains the low order bits. RESPONSE:

START OF

FRAME

ADDRESS FIELD

FUNCTION CODE

No. OF BYTES

D0, D1, …, Dn ERRORCHECK

END OF

FRAME

START OF FRAME = Starting message marker. ADDRESS FIELD = Device address (01...F7 HEX) (1byte). FUNCTION CODE = Operation code ( 03 HEX) (1 Byte). No. OF SEND BYTES = Number of data bytes ( 00...?? HEX) (1 byte). 1 register requires 2 data bytes. D0, D1, .., Dn = data bytes ( 00...?? HEX) (Nr. of register x 2 = n. byte). ERROR CHECK = Check sum. END OF FRAME = End message marker .


SETUP OF THE PARAMETERS (Function Code $ 10) Write values into a sequence of holding registers (2X references). WARNING: It is possible to write more than one variable at the same time only if their addresses are consecutive and the variables on the same line cannot be divided. QUERY:

START OF

FRAME

ADDRESS FIELD

FUNCTION CODE

START ADDRESS

No. OF REGISTERS

No. OFBYTES

D0, D1, …, Dn ERROR CHECK

END OF

FRAME

START OF FRAME = Starting message marker. ADDRESS FIELD = Device address ( 01...F7 HEX) (1 byte). FUNCTION CODE = Operation code ( 10 HEX) (1 byte). START ADDRESS = First register address to be written (2 byte). No. OF REGISTER = Number of registers to be written (1 to 4,...) (2 byte). No. OF BYTES = Number of data bytes (HEX) (1 byte): 1register requires 2 data bytes. D0,D1,..,Dn = Data bytes ( 00...? HEX) (1 byte) (Nr. of register x 2 = n. byte). ERROR CHECK = Check sum. END OF FRAME = End message marker. The normal response returns the slave address, function code, starting address and quantity of register preset. RESPONSE:

START OF

FRAME

ADDRESS FIELD

FUNCTION CODE

START ADDRESS

No. OF REGISTERS

ERRORCHECK

END OF

FRAME

START OF FRAME = Starting message marker. ADDRESS FIELD = Device address ( 01...F7 HEX) (1 byte). FUNCTION CODE = Operation code (10 HEX) (1 byte). START ADDRESS = First register address to be written (2 byte). No. OF REGISTER = Number of registers to be written (2 byte). ERROR CHECK = Check sum. END OF FRAME = End message marker.


REPORT SLAVE ID (Function Code $ 11) This function returns the type of the instrument. Broadcast is not supported. The Query and the Response messages are the following: QUERY:

START OF

FRAME

ADDRESS FIELD

FUNCTION CODE

ERROR CHECK

END OF

FRAME

START OF FRAME = Starting message marker. ADDRESS FIELD = Device address (01...F7 HEX) (1 byte). FUNCTION CODE = Operation code ( 11 HEX) (1 byte). ERROR CHECK = Check sum. END OF FRAME = End message marker. RESPONSE:

START OF

FRAME

ADDRESS FIELD

FUNCTION CODE

BYTE COUNT

SLAVEID

ERROR CHECK

END OF

FRAME

START OF FRAME = Starting message marker. ADDRESS FIELD = Device address (01...F7 HEX) (1 byte). FUNCTION CODE = Operation code (11 HEX) (1 byte). BYTE COUNT = Number of data bytes (16 HEX) (1 byte). SLAVE ID = Slave ID identifier (5C HEX) (1 byte). ERROR CHECK = Check sum. END OF FRAME = End message marker. The normal response has the slave ID identifier 5C HEX. REPORT SLAVE ID EXAMPLE QUERY RESPONSE Field Name Example (Hex) Field Name Example ( Hex) Slave Address 01 Slave Address 01 Function Code 11 Function Code 11 Error Check (CRC) ?? Byte count 02 ?? Slave ID 5C Error Check (CRC) ?? ??


ERROR MESSAGE FROM SLAVE TO MASTER When a slave device receives a not valid query, it does transmit an error message. RESPONSE:

START OF

FRAME

ADDRESS FIELD

FUNCTION CODE

ERROR CODE

ERRORCHECK

END OF

FRAME

START OF FRAME = Starting message marker. ADDRESS FIELD = Device address ( 01...F7 HEX) (1 byte). FUNCTION CODE = Operation code with bit 7 high (1 byte). ERROR CODE = Message containing communication failure (1 byte). ERROR CHECK = Check sum. END OF FRAME = End message marker. ERROR EXAMPLE QUERY RESPONSE Field Name Example (Hex) Field Name Example (Hex) Slave Address 01 Slave Address 01 Function Code 03 Function Code 83 (1) Starting Address Hi 00 Error Code 02 (2) Starting Address Lo 00 Error Check (CRC) ?? Number Of Word Hi 00 ?? Number Of Word Lo 05 Error Check (CRC) ?? (1): Function Code transmitted by master with bit 7 high. ?? (2): Error type: 01 = Illegal Function 02 = Illegal data address 03 = Illegal data value


Modbus RTU Table Address

Parameter Format General description Dec Hex

Read only Function 0x03 1 0001 Model description F10 7 0007 Hardware version F10 23 0017 Hardware revision F10 25 0019 Hardware options F10 28 001C Firmware version F10 ‘xx’ (x.x) 29 001D Number of windows F10 ‘xx’ Read only Function 0x03 30 001E Window 1 status F11 Window off, on, slow, fast,

intermittent flashing 31 001F Window 2 status F11 32 0020 Window 3 status F11 33 0021 Window 4 status F11 34 0022 Window 5 status F11 35 0023 Window 6 status F11 36 0024 Window 7 status F11 37 0025 Window 8 status F11 38 0026 Window 9 status F11 39 0027 Window 10 status F11 40 0028 Window 11 status F11 41 0029 Window 12 status F11 42 002A Alarm point inputs F12 43 002B Cumulative output relay status F13 44 002C Audible output relay status F13 45 002D Alarm input contacts F14 NO or NC 46 002E Alarm sequence F15 Read / Write Function 0x03, 0x10 47 002F Audible output relay configuration F16 NO or NC 48 0030 Cumulative output relay configuration F16 Write only Function 0x10 4528 11B0 Device address 1 to 247 4529 11B1 Baud-rate F17 4531 11B3 Alarm delay F18 Write only Function 0x10 4532 11B4 Ack button F19 ACK 4533 11B5 Reset button F19 RESET


Description of Field Format Type Description F10 Product info ASCII character F11 Window status 0 = window off

1 = window on 2 = slow flashing 3 = fast flashing 4 = intermittent flashing

F12 Alarm point input status 0 = normal 1 = fault bit 0 = min input number bit 11 = max input number

F13 Audible and cumulative relay status Audible relay 0 = off 1 = on Cumulative relay 0 = no alarm 1 = at least one alarm present

F14 Configuration alarm inputs for use with NO or NC field contacts

0 = NC 1 = NO

F15 Alarm sequence selected 0 = F1M 1 = F3A 2 = F1A 3 = M 4 = R8 5 = M5 6 = A

F16 Relay configuration 0 = Failsafe 1 = Non-failsafe

F17 Communication baud-rate 0 = 9600 bps 1 = 19200 bps 2 = 38400 bps

F18 This option will prevent the alarm from occurring unless it has been present for a pre-set period time

0 = 10 ms 1 = 15 ms 2 = 100 ms 3 = 300 ms 4 = 500 ms 5 = 1 s 6 = 5 s 7 = 1 min 8 = 5 min 9 = 15 min 10 = 30 min 11 = 1 h

F19 Button command Set '1' to trigger, '0' no action

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