Modbus Communication between AC800M(CI853) to Siemens S7300???
You have to use MODBUS RTU Communication Library
The MODBUS RTU Communication library (ModBusCommLib) contains data
types and function block types for communication via the MODBUS protocol.
MODBUS can be used for point-to-point or multidrop communication.Communication takes place serially and asynchronously, based on the master/slave principle, and in half duplex. MODBUS slave communication is not supported, only master communication.
You have to create MBConnect in that you define your channel as your Ci853 position with port number ex: CI853 position 1 & u r using port1 then channel no will be 1.1
& define the partner number u ask for simens both are of type string Then define MBread here you have to define the start address means what type of function codes you are using but enusre ID should be common for both like ID1 connected to MBconnect same should be connected to MBread for communication between these two & if you want communication in intervals then insert pulsgenerator between these block with period & pulse time
Look in Apps:
The first one is step-by-step instruction of Modbus communication.
At Siemens side you need CP340 or CP341 communication module with appropriate interface and your own Modbus code, or CP341 and loadable Modbus slave driver.
Follow the steps to set up communication with CI853 only.
1.You can configure CI853 as Modbus Master Only it can't support as Slave.
2.You have to lay the serial cable between CI853 & RS485 to RS232 converter with cable length not more than 50feet(15mtr) & from converter(2wire/4wire) to S7300, the cable length should supports upto 1.2Km.
3.Insert the Hadware lib hardware modbus com lib in the controller hardware where you need to define the CI853.
3.1 Define the Modbus parameters like baud rate,parity, etc.
4.Build the serial program in the control builder M by using Modbus comm lib you have to insert this library to the correponding applicaiton where you are going to use these blocks MBconnect,Pulse generator,MBread(with 32 registers in one read block)
5.Define the channel no=CI853Position.Port no you are using.(ex:for position1 ci853 combinations are 1.1(for port 1),1.2(port2))
6.Define the Partner name=S7300 device no(slave no).
7.Define the starting address in the MBread block with
Coil = 00001-09999 address starts from '%QX10#0000'
Discrete Input = 10001-19999 address starts from '%IX10#0000'
Input Register = 30001-39999 address starts from '%IW10#0000'
Holding Register = 40001-49999 address starts from '%QW10#0000'
8.Ensure ID channel should be same for MBconnect & MBread for communication with perticuler port(means its unique for ports if you are using defferent port then use deffrent ID for that communication)
Hope it clears your doubt