Skip to Content

SiePortal

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

SiePortalDeutsch

Search

Home
Support Support
{{(apiData.Support | filter:{'rank':1}:true)[0].title}} Support
- Menu temporary not available
- Menu temporary not available
- Menue temporary not available
- {{item.title}}

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 master and slave communication problem

Created by: Maro at: 6/14/2012 1:49 PM (7 Replies)

Rating (0)

Thanks 0

8 Entries

6/14/2012 1:49 PM	Rate (0)
Maro Posts: 9 Rating: (0)	Dear all, I have a modbus master slave communication problem.!! Please i need your help. for this see attachement please Best regard, Maro Attachment Modbus.PDF (270 Downloads)
Maro Posts: 9 Rating: (0)
Suggestion To thank Quote Answer

6/14/2012 2:54 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 3/22/2025 Posts: 12344 Rating: (2707)	Hello maro; A quick look on your pdf documents shows that your basic settings seem OK. By the way, congratulations for the presentation, it really shows that you have done your own development and research, and that you are not looking for a handout. now, 2 things from my experience with the CP341: - the TX LED should normally blink as soon as the Modbus send function is active. Check the call of your send block and validatehow it is called, and that it does address the correct CP address. - the RX LED will only blink if the CP detects a correct electrical connection with the communication partner. How have you setup the Modbus RS485 cable? As per the manual, I hope(see the following attachment)? Hope this helsp, Daniel Chartier Attachment Modbus RS485 connexions.JPG (225 Downloads)

Suggestion To thank Quote Answer

6/14/2012 2:59 PM	Rate (0)
smiffy Platinum Expert Joined: 1/17/2007 Last visit: 3/10/2025 Posts: 1557 Rating: (540)	What status messages are you getting from the blocks?
	Programming today is the race between software engineers building bigger and better idiot proof programs, and the universe producing bigger and better idiots. So far, the universe is winning...
Suggestion To thank Quote Answer

6/14/2012 5:58 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (324)	Hello Maro, I recommend to use presetting of the receiving line of R(A) 0V and R(B) 5V. Regards, Kaulquappe
Kaulquappe Posts: 3093 Rating: (324)
Suggestion To thank Quote Answer

6/15/2012 2:53 PM	Rate (0)
Maro Posts: 9 Rating: (0)	Thank you everyone for yours answers, i appreciate it. To Dchartie: My programe at the master side is looking like: (Master) (Dchartie 1): FB7(Modbus control) is called in OB1 as usuallFB7 looking like: see network 3(copy data to be send), network 4 (FC81 send data), network 5(FC82 receive data) and network 6.see attachements please. To smiffy: (see also attachements) The status message of the all bloks of master as well of slave: The status is changing from 0 to 7695(16#1E0F) each cycle The error is changing from 0 to 1(each cycle) To Kaulquappe:It doesn’t help . It stil not working guys, very strange. Thanks. Maro Attachment Modbus 2.PDF (175 Downloads)
Maro Posts: 9 Rating: (0)
Suggestion To thank Quote Answer

6/15/2012 3:22 PM	Rate (0)
smiffy Platinum Expert Joined: 1/17/2007 Last visit: 3/10/2025 Posts: 1557 Rating: (540)	Ok you are getting an error during the sending of the request (P_SND_RK_WORK_STATUS = 1E0F). However, to ascertain why this is happening, we need the SFCSTATUS code from the P_SND_RK instance data block (P_SND_RK_DATA.SFCSTATUS).
	Programming today is the race between software engineers building bigger and better idiot proof programs, and the universe producing bigger and better idiots. So far, the universe is winning...
Suggestion To thank Quote Answer

6/15/2012 3:31 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (324)	Hello Maro, I recognized two things: - you use the cable for RS422 4- wire, but you parameterized RS485 2-wire. - you try to send 400 byte. Modbus communication is not able to do that. The erorr 1E0F indicates, that something with the data source is not ok. How long is your Send DB? For the Modbus slave project you should use FB80 of the Modbus library. Regards, Kaulquappe
Kaulquappe Posts: 3093 Rating: (324)
Suggestion To thank Quote Answer

6/15/2012 3:56 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (324)	Hello Maro, now I got why your receive error 1E0F, you used R_TYP = D but it should be R_TXP = X. And R_NO should be empty. Regards, Kaulquappe
Kaulquappe Posts: 3093 Rating: (324)
Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on