Siemens SIMATIC S7 Manual page 49

Error messages of FB MODBUS MODBUSPN at the output STATUS_MODBUS
STATUS Event text
(Hex)
A005 S7 is client:
An invalid value for the parameter LENGTH is given.
S7 is Server:
The number of registers/bits in the request telegram is
invalid.
Range of values:
Read coils/inputs: 1 to 2000
Write coils: 1 to 800
Read registers: 1 to 125
Write holding registers: 1 to 100
A006 The given range of registers defined with DATA_TYPE,
START_ADDRESS and LENGTH does not exist in
data_type_1 to data_type_8.
A007 Only if S7 is client:
An invalid monitoring time RECV_TIME or CONN_TIME
is parameterized.
The RECV_TIME has to be at least 20 ms, CONN_TIME
100ms
A009 Only if S7 is client:
The received transaction identifier TI is not equal to the
sent one.
The connection is terminated.
A00A Only if S7 is client:
The received UNIT is not equal to the sent one.
A00B S7 is client:
Received function code is not equal to the sent one.
S7 is server:
An invalid function code was received.
A00C The received byte count does not match the number of
registers.
The connection is terminated.
A00D Only if S7 is client:
The register or bit address respectively the number of
registers or bits in the response telegram is not equal to
the one in the request telegram.
A00E The length indicated in the MODBUS-specific telegram
header does not match the number of registers/bits or
the byte count in the telegram. The FB ignores all data.
The connection is terminated.
MODBUS / TCP communication via the integrated PN interface of the CPU
2XV9450-1MB02; Manual edition 2.1
Remedy
S7 is Client:
Correct the parameter
LENGTH.
S7 is Server:
Modify the number in the
request telegram.
S7 is Client:
Correct the parameter
combination DATA_TYPE,
START_ADDRESS, LENGTH.
S7 is Server:
Modify the request of the client
or correct the parameterization
of data_type_x.
Correct the parameterization.
Verify the data of the
communication partner with the
help of a telegram trace.
S7 is client:
Verify the data of the
communication partner with the
help of a telegram trace.
S7 is server:
The FB MODBUS only
supports the function codes 1,
2, 3, 4, 5, 6, 15 and 16.
Verify the data of the
communication partner with the
help of a telegram trace.
Diagnosis
7-7