5. CONFIGURATION
Write Single Register (FC 06): 1
Write Multiple Coils (FC 15): 1968
Write Multiple Registers (FC 16): 123
Mask Write Register (FC 22): 1
Read/Write Multiple Registers (FC 23): 121
Write Data Range: this field shows the MODBUS write data range configured for each request. The initial address, along
with the read data size will result in the range of write data for each request.
Diagnostic Variable: The MODBUS request diagnostics configured by symbolic mapping or by direct representation, are
stored in variables of type T_DIAG_MODBUS_RTU_MAPPING_1 for Master devices and T_DIAG_MODBUS_ETH_CLIENT_1
for Client devices and the mapping by direct representation are in 4-byte and 2-word, which are described in Table 91 (n is the
value configured in the %Q Start Address of Diagnostics Area field).
Direct Repre-
sentation
Variable
Diagnostic variable of type
T_DIAG_MODBUS
_RTU_MAPPING_1.*
Size Description
Communication status bits:
%QX(n).0
byStatus.
bCommIdle
BIT
Communication idle (waiting to be exe-
cuted).
%QX(n).1
byStatus.
bCommExecuting
BIT Active communication.
%QX(n).2
byStatus.
bCommPostponed
BIT
Communication delayed, because the max-
imum number of concurrent requests was
reached. Deferred communications will be
carried out in the same sequence in which
they were ordered to avoid indeterminacy.
The time spent in this State is not counted
for the purposes of time-out. The bCom-
mIdle and bCommExecuting bits are false
when the bCommPostponed bit is true.
%QX(n).3
byStatus.
bCommDisabled
BIT
Communication disabled. The bCommIdle
bit is restarted in this condition.
%QX(n).4
byStatus.
bCommOk
BIT
Communication terminated previously was
held successfully.
%QX(n).5
byStatus.
bCommError
BIT
Communication terminated previously had
an error. Check error code.
%QX(n).6
byStatus.
bCommAborted
BIT Not used in MODBUS RTU Master.
%QX(n).7
byStatus.
bDiag_7_reserved
BIT Reserved
Last error code (enabled when bCommError = true):
%QB(n+1)
eLastErrorCode
MASTER_ERROR
_CODE (BYTE)
Informs the possible cause of the last error
in the MODBUS mapping. Consult Table
114 for further details.
Last exception code received by master:
%QB(n+2)
eLastExceptionCode
MODBUS _EXCEP-
TION (BYTE)
NO_EXCEPTION (0)
FUNCTION_NOT_SUPPORTED (1)
MAPPING_NOT_FOUND (2)
ILLEGAL_VALUE (3)
ACCESS_DENIED (128)*
MAPPING_DISABLED (129)*
IGNORE_FRAME (255)*
112