SiePortal

The integrated platform for your product selection, buying and support workflow - bringing together Industry Mall and Online Support.

Products & Services
- Menu temporary not available
- Menue temporary not available
- {{item.title}}
Support Support
{{(apiData.Support | filter:{'rank':1}:true)[0].title}} Support
- Menu temporary not available
- Menue temporary not available
- {{item.title}}
MySiePortal MySiePortal
{{(apiData.MySiePortal | filter:{'rank':1}:true)[0].title}} MySiePortal
- Menu temporary not available
- Menue temporary not available
- {{item.title}}
Cart ({{apiData.CartCount}})

Navigation

modbus INIT

4/9/2013 12:29 PM	Rate (0)
sachin10 Posts: 4 Rating: (0)	hello guys, I am totally new at PLCs. i have read through books and i m using s7-200 right now. i have used modbus init function and slave function and i have filled up the details that the function asked. now i have test progrmme called MODBUS MAT to check the status. Basically i just want the response like valid response received. but everytime when i start polling it says time out. is there any parameter i need to change to get the valid response. i used mode, slave address 1.baud rate 9600. only for test purpose i used plc as a slave. Please reply it. I am struggling for this issue from 3 days. Thanks
sachin10 Posts: 4 Rating: (0)
Suggestion To thank Quote Answer

4/9/2013 1:13 PM	Rate (0)
adrian1982 Posts: 37 Rating: (3)	have you tried siemens example? https://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&objId=27832512&load=treecontent&lang=en&siteid=cseus&aktprim=0&objaction=csview&extranet=standard&viewreg=WW
adrian1982 Posts: 37 Rating: (3)	Last edited by: adrian1982 at: 4/9/2013 1:14 PM
Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users Kahl

4/9/2013 1:59 PM	Rate (0)
sachin10 Posts: 4 Rating: (0)	hello Adrian, yes, i have looked at this example but this example shows with two PLC whereas in my case i have only one PLC which is connected to pc through port 1 and modbus mat program to port 0. i have choosen plc as a slave but how can i choose master as i have only test prog. i have just MBUS_INIT function and MBUS_SLAVE in programe. i downloaded to PLC and with modbus MAT i just need confirmation that data has been received rather than time out error.
sachin10 Posts: 4 Rating: (0)
Suggestion To thank Quote Answer

4/9/2013 3:21 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (324)	Hello Sachin10, the time out can be caused by different things: - wrong data frame (both communication partners need the identical parameterization) - wrong slave address - wrong wiring (cable) Regards, Kaulquappe
Kaulquappe Posts: 3093 Rating: (324)
Suggestion To thank Quote Answer

4/10/2013 6:34 AM	Rate (0)
adrian1982 Posts: 37 Rating: (3)	do you use an usb converter from PLC to PC or a serial? Sometimes when i use usb/rs485 converter for testing modbus comunications i get an time-out because a delay in the signal when it's converted Try modifying both in PC program and in PLC the baudrate. From the Siemens example you can take the parameters from the master PLC and set your PC program (ModBus Address, Baudrate, Parity, and Registers)
adrian1982 Posts: 37 Rating: (3)
Suggestion To thank Quote Answer

Share this page:

Share this page on...