Guest

Hi

I would like to introduce myself as krishnakumar working for a US based semiconductor industry in India.
I Have a query regarding Profibus communication.The Devices which are to be interfaced are siemens PLC S7400 and DIRIS A40 Multi measuring unit.
I got the GSD file and i have installed.

My Query is regarding the programming part.
I have to create an FB for establishing a communication between DIRIS and PLC.
To establish a communication , should i Use SFC 14 & 15 to read/write data from DP slave..OR ..Can it be done with out using these SFC`s.

when to use SFC`s to Communicate with DP slave. or can i fetch the data with Load/Transfer Instructions..

Krishnakumar D

Import-User-1

Importing a Technical Question of an User

Guest wrote:

Hi

I would like to introduce myself as krishnakumar working for a US based semiconductor industry in India.
I Have a query regarding Profibus communication.The Devices which are to be interfaced are siemens PLC S7400 and DIRIS A40 Multi measuring unit.
I got the GSD file and i have installed.

My Query is regarding the programming part.
I have to create an FB for establishing a communication between DIRIS and PLC.
To establish a communication , should i Use SFC 14 & 15 to read/write data from DP slave..OR ..Can it be done with out using these SFC`s.

when to use SFC`s to Communicate with DP slave. or can i fetch the data with Load/Transfer Instructions..

Krishnakumar D

315-2DP

But if I'm trying to read 3,5, 16 or 32 bytes...

function returns to MW20 W#16#80B1 and doesn't write data to DB20.

Where is the problem? I don't know how to cope with this. :(

fritz

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

315-2DP

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?

fritz

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.