Modbus通信協議為Modicon PLC廠家所定義的.
完整之資料可以從許多相關網站下載, (如 http://www.gkong.com)
本公司之驅動器僅使用Modbus之一部份功能, 茲敘述如下:
MODBUS(RTU) protocol in PDS & PDAn series
The RS485 port in PDS & PDAn series can be assigned as MODBUS(RTU) mode.
With this commonly used protocol, user can easily establish a low cost
network
between PC/PLC/HMI and our drives.
1. How to configure PDS serial port working in modbus protocol?
Set
following parameters:
|
Parameters
|
Set value
|
Description
|
|
Pr.120
|
=1, JPS Mod bus(RTU)
=3, Standard Modbus(RTU)
|
Protocol select
|
|
Pr.121
|
=0, 4800bps
=1, 9600bps
=2, 19200bps
=3, 38400bps
|
Baud rate select
|
|
Pr.122
|
=0, 1 stop bit
=1, 2 stop bit
|
Stop bit select
|
|
Pr.123
|
ID address 00~99
|
Write Stack Buffer
|
|
Pr.124
|
0 (read only, must <=25 to prevent write data loss)
|
Write Stack Buffer
|
|
Pr.125
|
=0, Even Parity
=1, Odd Parity
=2, No Parity
|
RTU protocol
|
|
Pr.129
|
elapse time between digit
|
in milli-second
|
2. How to configure PDAn serial port working in modbus protocol?
Set
Pr.93 parameters for RS485 serial port,
Pr.93= 2 B . ID, where
ID: Identification
address ranging from 01~99
B=0 4800bps, 2stopbits
B=1 9600bps, 2stopbits
B=2 19200bps,
2stopbits
B=3 reserve
B=4 4800bps, 1stopbits
B=5 9600bps, 1stopbits
B=6 19200bps,
1stopbits
B=7 reserve
3. Protocol summary
Please refer to standard MODBUS protocol
definition.
For simplicity, only six basic functions of MODBUS protocol were build.
They are:
MODBUS function code -01(hex): BIT read
MODBUS function code -05(hex): BIT write
MODBUS function code -0f(hex): multiple BIT write
MODBUS function code -03(hex): WORD read
MODBUS function code -06(hex): WORD write
MODBUS function code -03(hex): LONGWORD read
MODBUS function code -10(hex): LONGWORD write
4. Register or Parameter mapping
PDS series
BIT
DI1~DI6 mapping to
bit1~bit6
DO1~DO3 mapping to
bit17~bit19
WORD
Pr.000~Pr.999 mapping
to WORD-000~WORD-999
LONGWORD(even address)
Pr.001/Pr.000 mapping
to LONGWORD-000
Pr.003/Pr.002 mapping
to LONGWORD-002 ~
Pr.999/Pr.998 mapping
to LONGWORD-998
***note: For PDS
drive, longword Read/Write function, high word data store
in higher register
address.
PDAn series
BIT
DI1~DI6 mapping to
bit1~bit6
DO1~DO3 mapping to
bit17~bit19
WORD
Pr.00~Pr.99 mapping to
WORD-00~WORD-99
LONGWORD
Not used
