S7-300 MB_TPC doesn't work with retrieve of data

Hi, 

   I am using S7-300 CPU315-2PN/DP to work like ModbusTCP client and acquire data at every second from the third Party Modbus Device. I am using TAI portal for S7-300 PLC programming.

After little modification in the modbusTCP example as in the attached TAI portal Program.

But i can connect with the device but not able to get data from the holding register.

In my case PLC IP address is 192.168.1.101 and HRM-0800 modbus device address is 192.168.1.112.

OB100 is programmed as

--------------

// for initialization

OB1 is programmed 

----------------------------------

---------------------

MODBUS_PARAM is programmed 

------------

for client address 192.168.1.112

-----------------------------

If you can guide me why i am not getting data on the CPU data block, i will be thankful.

Thanks

------------------------------------------------------------------------------------------
Split from connect CPU315-2PN/DP and third party ModbusTCP.

Hello,

answer is very simple, you call Modbus block in OB100 only and not in cyclic block. Really hope you understand procedure what is required to do because your step hasn't sence.

Hi,

  I tried with OB1 also but same result.

I put 

in OB100 and reset in OB1.  But not able to get date.

Thanks

Thank you for your reply.

If i put sequence on OB1 as below, is ok?

L     t#500ms
T     "CONTROL_DAT".RECV_TIME

L     t#5s
T     "CONTROL_DAT".CONN_TIME


// Reset trigger after job has started
A     "CONTROL_DAT".ENQ_ENR
R     "CONTROL_DAT".ENQ_ENR
S     "CONTROL_DAT".ENQ_ENR

// For cyclic data exchange remove the comment characters
O     "CONTROL_DAT".DONE_NDR
O     "CONTROL_DAT".ERROR
S     "CONTROL_DAT".ENQ_ENR

A     "CONTROL_DAT".DONE_NDR
CLR
=     "CONTROL_DAT".ENQ_ENR
JCN   Err

// Job finished without error
L     "CONTROL_DAT".Count_Done//for test purposes
+     1
T     "CONTROL_DAT".Count_Done

// You can set the parameters for the next job here
// It is set in comments to give you the possibility
// to use the variable table for changes during test

L     2
T     "CONTROL_DAT".UNIT

L     3
T     "CONTROL_DAT".DATA_TYPE

L     10
T     "CONTROL_DAT".START_ADDRESS

L     5
T     "CONTROL_DAT".LENGTH

CLR
=     "CONTROL_DAT".WRITE_READ

SET
=     "CONTROL_DAT".ENQ_ENR//job trigger

JU    End

Err:  A     "CONTROL_DAT".ERROR
JCN   End

// Job finished with error

L     "CONTROL_DAT".Count_Error//for test purposes
+     1
T     "CONTROL_DAT".Count_Error

L     "CONTROL_DAT".STATUS
T     "CONTROL_DAT".Save_STATUS//for static display in VAT

// STATUS_FUNC => Save_STATUS_FUNC
CALL  BLKMOV
blk_type:=Any
SRCBLK  :="CONTROL_DAT".STATUS_FUNC
RET_VAL :=#BLKMOV_RetVal
DSTBLK  :="CONTROL_DAT".Save_STATUS_FUNC

End:  NOP 0

 Hello,

Duris_I

Hello,

answer is very simple, you call Modbus block in OB100 only and not in cyclic block. Really hope you understand procedure what is required to do because your step hasn't sence.

  hope I see it ok but again, where is your call of MB_TCP block? You still change probably only signals for control but you don't call that communication block.

Hi Duris,

  I put it in OB100 before not it is in OB1.

CALL  MODBUSPN , "MODBUSPN_DB" also in OB1.

I kept

SET
=     "CONTROL_DAT".Init

only in  OB100. Rest is in OB1.

Thanks

The result with online is attached

With "JCN Err"  and commented "JCN Err"

The complete project is attached for your reference..

The PLC address is 192.168.1.101

The modbusTCP device IP address is 192.168.1.112.

Thanks

Vishnu