DKG-119J User Manual V-32
(09.07.2012)
- 28 -
The unit offers the possibility of MODBUS communication via its logic level 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 MODBU
S 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
0003
R
16bit
x1
Genset Phase L1 voltage
0006
R
16bit
x1
Genset Phase L1 current
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_4: auto mode
bit_5: stop mode
bit_6: run mode
A logic level to RS-232 converter is necessary
in order to connect the unit to modem.
8. MODBUS COMMUNICATION