Datakom DKG-309 - Modbus Communication; Modbus Connection Options; Modbus Register Mapping

DKG-309 User Manual V-02
(11.05.2009)
- 23 -
8. MODBUS COMMUNICATION
The unit offers the possibility of MODBUS communication via its RS232 serial port.
The connection to the MODBUS master may be done in 3 ways:
1) RS232 connection using directly the RS232 port provided.
2) RS422/485 connection using external RS422/485 converter.
3) Modem connection using external modem.
The MODBUS mode is activated by assigning a controller address to the unit using MODBUS
Address program parameter. The possible address range is 1 to 144. Setting the address to 0 will
disable the MODBUS mode and allow communication under RAINBOW protocol.
The MODBUS properties of the unit are:
-Data transfer mode: RTU
-Serial data: 9600 bps, 8 bit data, no parity, 1 bit stop
-Supported functions:
-Function 3 (Read multiple registers)
-Function 6 (Write single register)
Detailed description about the MODBUS protocol is found in the document “Modicon Modbus
Protocol Reference Guide”. The web address is: www.modbus.org/docs/PI_MBUS_300.pdf
Below is a limited shortlist of readable registers. For the detailed Modbus Application
Manual and a complete list of registers please contact DATAKOM.
ADDRESS
(hex)
R /
W
DATA
SIZE
COEFFICIENT
DESCRIPTION
0000 R 16bit x1 Mains Phase L1 voltage
0001 R 16bit x1 Mains Phase L2 voltage
0002 R 16bit x1 Mains Phase L3 voltage
0003 R 16bit x1 Genset Phase L1 voltage
0004 R 16bit x1 Genset Phase L2 voltage
0005 R 16bit x1 Genset Phase L3 voltage
0006 R 16bit x1 Genset Phase L1 current
0007 R 16bit x1 Genset Phase L2 current
0008 R 16bit x1 Genset Phase L3 current
000C R 16bit x1 Mains Phase L12 voltage
000D R 16bit x1 Mains Phase L23 voltage
000E R 16bit x1 Mains Phase L31 voltage
000F R 16bit x1 Genset Phase L12 voltage
0010 R 16bit x1 Genset Phase L23 voltage
0011 R 16bit x1 Genset Phase L31 voltage
0012 R 16bit x10 Mains frequency
0013 R 16bit x10 Genset frequency
0016-0017 R 32bit x256 Genset active power: this 24 bit signed register holds
the genset active power multiplied by 256. Least
significant 16 bits are in the register 0016h. Most
significant 8 bits are in the LSB of the register 0017h.
0018 R 8bit x100 Power factor multiplied by 100 (signed byte). Negative
values indicate a capacitive power factor.
002A R 16bit x1 Engine speed (rpm)
002B R 16bit x10 Oil pressure in bars.
002C R 16bit x1 Coolant temperature in degrees C.
002D R 16bit x1 Fuel level as %
002F R 16bit x10 Battery voltage
003D R 8bit - Operating mode
bit_3: manual mode
bit_4: auto mode
bit_5: off mode
bit_6: test mode
bit_7: load test mode