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Profibus Communication - Access to I/O Data
Created by: Import-User-1 at: 7/29/2008 1:16 PM (10 Replies)
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| 7/29/2008 2:30 PM | |
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Posts: 2348 Rating:
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You can use L/T instructions. But in this case data consistency guaranteed is only 1,2 or 4 bytes. |
| 7/30/2008 8:35 PM | |
Joined: 12/22/2006 Last visit: 1/25/2022 Posts: 1742 Rating:
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Hello, If you put the data of the slave in the process image, the complete data is consistent. SFC14 and SFC15 can be avoided. Access to the data is done via Laod and transfert. See FAQ : http://support.automation.siemens.com/WW/view/en/8751062 |
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Best regards |
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| 7/14/2009 12:11 PM | |
Joined: 10/7/2005 Last visit: 9/14/2025 Posts: 3049 Rating:
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Dear 315-2DP Error W#16#80B1 means "The length specified in the RECORD parameter is incorrect" (I'm probably telling you how to suck egss here, but just in case you arn't aware of this, if you selectthe SFC59 and press <F1> you'll get the inbuitl help for it.) Note that you can only access the data of ONE module (aka DP id) in your DP Slave with a SFC14 call and I wonder if you have changed yourDP Slave module configuration accordingly to "support" the read of 3,5 ,16 or 32 bytes. The other thing to look out for is to obviously haveyour destination DB long enough. Anyway, below is link which also contains a nice FAQ pdf which I trust you'll find interesting and helpful. Consistent data, overview and application in distributed I/O I hope this helps |
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Cheers |
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| 7/15/2009 1:59 PM | |
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Posts: 4 Rating:
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Dear fritz, Thank you for yourquick answer and for link to a PDF file. It was very helpful but I can't still solve all problems. Destination DBwas long enough. I changed in HW config consistency data from "UNIT" to "TOTAL LENGTH" (see attachment). Now when I try read 10 bytes CALL SFC 14 LADDR :=W#16#13A RET_VAL:=MW20 RECORD :=P#DB20.DBX0.0 BYTE 10 function returns toMW20: 80A0 - Access error detected while the I/O devices were being accessed. What's wrong with the configuration? |
Last edited by: 315-2DP at: 7/15/2009 2:04 PM |
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| 7/15/2009 3:07 PM | |
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Joined: 10/7/2005 Last visit: 9/14/2025 Posts: 3049 Rating:
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good question dear 315-2DP! I can't see anyhting wrong in your latest configuration (i.e. SFC14 call parameters match up with HWconfig). Silly question: Did you download the HWconfig? (I presume the answer is yes). I never had this "80A0 - Access error detected while the I/O devices were being accessed" errorbefore, but wonder if your DP Slave itself supports the configuration thatit's GSD file allowed you to do in the HWconfig. I suggest toverifythe following: Disable the SFC14 call, download the HWconfig and verify that the bus is healthy (NO BF-bus faultLED is on). This means that your DP Slave accepted the chosen I/O configuration. Let us know the outcome and if anyone else out there has had the "80A0 - Access error detected while the I/O devices were being accessed" before and/or knows possible reasons for it, please let us know too. |
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Cheers |
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| 7/16/2009 10:23 AM | |
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Posts: 4 Rating:
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More detailed HW config. |
| 7/16/2009 2:40 PM | |
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Joined: 10/7/2005 Last visit: 9/14/2025 Posts: 3049 Rating:
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Dear 315-2DP the "inserted module and configured model aren't identical" message for your DP Slave is a worry (on the bright side, until this is solved there is no need to worry about the SFC14 W#16#80A0 error, which cna very well be explained by this problem). One of the "jobs" of a (Class 1) DP Master (theS7 PLC in your case) is to parameterise and (I/O) configureeach DP Slave on bus startup (e.g. after HWconfigdownload, power failure of Slave or Master etc.). Once done with this, the DP Master will "check" (via a Diagnostic request message) if the parameterisation and configuration was succesful (which does not appear to be case here). Example: Let's say you have an"ordinary" DP Slave such as an ET200M I/O station and physically pluggedfour 32 channel DI cards into it. Inyour HWconfig however youconfigured three 32 channel DIcards and one 32 channel DQcard. This mismatch will lead to the same problem that you observe. I unfortunately have no experience with your DIRIS A40 DP Slave, but whateverI/O config you do in your HWconfig will need to be supported by the DP Slave. You said before that you were able to read 4 bytes from the DP Slave, so I assume that the node address is ok and that the bus in general is ok too. As such, I suggesttocheck the DIRIS manual and/or the supplier to find outmore about possible/supported I/O configurations and reasons for the observed problems. By the way, you'll find a wealth of free helpful manualsconcerning Profibus at www.profibus.comwhich I hope will come in handy one day. Good luck andkeep us posted |
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Cheers |
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