Diagnostic Messages Of The Fb Modbuscp - Siemens SIMATIC S7 Manual

6.2

Diagnostic Messages of the FB MODBUSCP

Messages at the
STATUS Output of
the FB
Error Messages of
the called SFCs
and FCs
Error messages of FB MODBUSCP
STATUS Event text
(Hex)
A002 The parameter end_x is less than start_x.
A003 The DB, to which MODBUS addresses shall be
mapped, is too short.
Minimum length:
registers: ( end_x – start_x + 1 ) ∗ 2
bits: ( end_x - start_x ) / 8 + 1
Other possible reasons:
•
•
A004 Applies only with CP is client:
An invalid combination of DATA_TYPE and
WRITE_READ is given.
A005 CP is client:
An invalid value for the parameter LENGTH is given.
CP is Server:
The number of registers/bits in the request telegram is
invalid. The CP sends an exception telegram.
Range of values:
Read coils/inputs: 1 to 2000
Write coils: 1 to 1968
Read registers: 1 to 125
Write holding registers: 1 to 123
OPEN MODBUS / TCP communication via CP343-1 and 443-1
2XV9450-1MB00; Manual edition 4.3
The block MOBUSCP has got 2 status outputs: STATUS and
STATUS_FUNC. STATUS displays all error numbers. STATUS_FUNC shows
the name of the function, which caused the error. STATUS is valid when
ERROR is TRUE. Below you can find a list of FB-specific error messages.
The FB MODBUSCP, MB_CPCLI and MB_CPSRV use the standard
functions SFC6, SFC20, SFC24, SFC51, SFC52, FC5 and FC6, or FC50 and
FC60. The error messages of these blocks are passed on to STATUS without
any changes.
In the diagnostics buffer or in the online help of SIMATIC Manager you will
find further details on these error messages, as well as in the SIMATIC
STEP7 NCM S7 Industrial Ethernet Manual.
Wrong initialization parameter (CP is client).
Wrong address area in the request telegram of
the client (CP is server). The CP sends an
exception telegram.
Diagnostics
Remedy
Correct the parameterization of
start_x and end_x
Extend the DB.
CP is Client: Correct the
parameters START_ADDRESS
or LENGTH
CP is Server:
Modify the request of the client.
Correct the parameters. Only
data type 1 or 3 can be written.
CP is Client:
Correct the parameter LENGTH.
CP is Server:
Modify the number of
registers/bits in the request
telegram.
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