Man L23/30DF, Руководство по проекту

Страница: 311 / 392

2
MAN Diesel & Turbo
M
od
bu
s RTU
p
rot
oc
ol
S
aC
oS
on
e.G
ENS
ET
_Co
m
m
un
icatio
n_
m
_en_
1.
7
2 Modbus RTU protocol
The Modbus RTU protocol is the standard protocol used for the communica-
tion from the GenSet.
The bus interface provides a serial connection. The protocol is implemented
according to the following definitions:
Modbus application protocol specification, Modbus over serial line speci-
fication and implementation guide,
Important
For serial Modbus communication the following hardware require-
ments must be observed:
Control Module S: Modbus RTU and Modbus ASCII possible
Gateway Module: only Modbus RTU available
There are two serial interface standards available:
RS422 – Standard, 4 + 2 wire (cable length <= 100m), cable type as
specified by the circuit diagram, line termination: 120 Ohms
RS485 – Standard, 2 + 2 wire (cable length <= 100m), cable type as
specified by the circuit diagram, line termination: 120 Ohms
2.1 Settings
The communication parameters are set as follows:
Modbus Slave SaCoS
Modbus Master Machinery alarm system
Slave ID (default) 1
Data rate (default) 57600 baud
Data rate
(optionally available)
4800 baud
9600 baud
19200 baud
38400 baud
115200 baud
Data bits 8
Stop bits
1
Parity None
Transmission mode Modbus RTU
2.2 Function Codes
The following function codes are available to gather data from the SaCoS
one
controllers:
Function
Code
Function Code
(hexadecimal)
Description
1 0x01 read coils
3 0x03 read holding registers
5 0x05 write coil
6 0x06 write single register
15 0x0F write multiple coils
16 0x10 write multiple registers