Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

MODBUS RTU RS485 Redundancy

Created by: PPPD at: 5/14/2014 2:27 PM (7 Replies)

Rating (0)

Thanks 2

8 Entries

5/14/2014 2:27 PM	Rate (0)
PPPD Advanced Member Joined: 7/19/2008 Last visit: 8/1/2023 Posts: 60 Rating: (8)	hi, Can any one please help me know how can we configure the redundancy with CP341. I know there is no straight away solution with respect to hardware. is it possible to do it using the software? What exactly we will configure in software.....

Suggestion To thank Quote Answer

5/14/2014 9:30 PM	Rate (0)
hdhosseini Diamond Member Joined: 1/28/2009 Last visit: 12/4/2023 Posts: 6824 Rating: (1351)	PPPD hi, Can any one please help me know how can we configure the redundancy with CP341. I know there is no straight away solution with respect to hardware. is it possible to do it using the software? What exactly we will configure in software..... Hello, What is your software platform? For an H-Set up , I suggest using CP341 on ET200M for increased availability. In master side , call FB7,FB8 from the library and form space for the request frame and receive in a DB. In master side, 2 instant calls can be differentiated by LADDR and slave address. In slave side, beside using FB80 to recieve data , develop an error detection logic to copy the data frrom intact link to target area! I hope this helps, Hamid Hosseini
	Demo Channel on Youtube
Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users S7 AUTOMAN

5/15/2014 7:26 PM	Rate (0)
R J Bronze Member Joined: 10/20/2009 Last visit: 4/3/2017 Posts: 215 Rating: (12)	Hi PPPD, There are two similar topics going on forum. Link is as below: limitations of CP341 when used for Modbus RTU communication https://www.automation.siemens.com/tf/WW/en/Posts/80106 S7-400H - CP441-2 - Redundant slave Modbus https://www.automation.siemens.com/tf/WW/en/Posts/46686
	Regards, R J =================================== Your ‘I CAN’ is more important than your ‘I.Q’
Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users Krrish !!

5/20/2014 8:09 AM	Rate (0)
PPPD Advanced Member Joined: 7/19/2008 Last visit: 8/1/2023 Posts: 60 Rating: (8)	hdhosseini PPPD hi, Can any one please help me know how can we configure the redundancy with CP341. I know there is no straight away solution with respect to hardware. is it possible to do it using the software? What exactly we will configure in software..... Hello, What is your software platform? For an H-Set up , I suggest using CP341 on ET200M for increased availability. In master side , call FB7,FB8 from the library and form space for the request frame and receive in a DB. In master side, 2 instant calls can be differentiated by LADDR and slave address. In slave side, beside using FB80 to recieve data , develop an error detection logic to copy the data frrom intact link to target area! I hope this helps, Hamid Hosseini Any sample pogram is available..... i actually have CP341 with S7400 H CPU stations. i understand tht we dump the data cmng to our system at 2 different places and then detect which card is active to decide whatdata exactly to be used for display or in logic. correct me if i m wrong inthe above quote

Suggestion To thank Quote Answer

5/20/2014 8:34 AM	Rate (0)
hdhosseini Diamond Member Joined: 1/28/2009 Last visit: 12/4/2023 Posts: 6824 Rating: (1351)	PPPD Any sample pogram is available..... i actually have CP341 with S7400 H CPU stations. i understand tht we dump the data cmng to our system at 2 different places and then detect which card is active to decide whatdata exactly to be used for display or in logic. correct me if i m wrong inthe above quote For master side, search for "S7HMODM3" in the forum, you will find more information.Also possible to find ordering data/ contact data in IT4INDUSTRY.This is an application for PCS 7. For STL/LAD/FBD ,it is not difficult to implemet the whole concept.
	Demo Channel on Youtube
Suggestion To thank Quote Answer

5/20/2014 12:33 PM	Rate (0)
R J Bronze Member Joined: 10/20/2009 Last visit: 4/3/2017 Posts: 215 Rating: (12)	Hi PPPD, Please go through below thread, it have one sample program: /tf/WW/en/Posts/30548 Also you can go to below links: https://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&lang=en&objid=61586633&caller=view
	Regards, R J =================================== Your ‘I CAN’ is more important than your ‘I.Q’
Suggestion To thank Quote Answer

5/21/2014 6:32 AM	Rate (0)
PPPD Advanced Member Joined: 7/19/2008 Last visit: 8/1/2023 Posts: 60 Rating: (8)	hi all, thanks for your suggesions i will try and implement and then revert with the exact solution. as explained it is easy to do using the STL will try and make a block for the same purpose.

Suggestion To thank Quote Answer

5/21/2014 9:08 AM	Rate (0)
R J Bronze Member Joined: 10/20/2009 Last visit: 4/3/2017 Posts: 215 Rating: (12)	Hi, For step7 there is library available of Modbus RTU, so dont make your own blocks. Use FB7(P_RCV_RK), FB8(P_SND_RK) & FB80(MODB_341) for the Modbus communication.
	Regards, R J =================================== Your ‘I CAN’ is more important than your ‘I.Q’
Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on