Details of the Implicit Exchange Objects of the T_COM_MB Type IODDT
(Original Document)
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At a Glance
The following tables present the implicit exchange objects of the T_COM_MB type IODDT which apply to Modbus communication.
Error Bit
The following table presents the meaning of the error bit CH_ERROR (%Ir.m.c.ERR).
Standard Symbol
Type
Access
Meaning
Address
CH_ERROR
EBOOL
R
Communication channel error bit
%Ir.m.c.ERR
Word Objects in Modbus Master Mode
The table below shows the meaning of the bits of the INPUT_SIGNALS word (%IWr.m.c.0).
Standard Symbol
Type
Access
Meaning
Address
DCD
BOOL
R
Data carrier detection signal
%IWr.m.c.0.0
RI
BOOL
R
Ring indicator signal
%IWr.m.c.0.1
CTS
BOOL
R
Ready to send signal
%IWr.m.c.0.2
DSR
BOOL
R
Data ready signal
%IWr.m.c.0.3
Word Object in Modbus Slave Mode
The language objects are identical to those of the Modbus master function. Only the objects in the following table differ
The table below shows the meaning of the bit of the INPUT_SIGNALS word (%IWr.m.c.0).
Standard Symbol
Type
Access
Meaning
Address
LISTEN_ONLY
BOOL
R
List mode only signal
%IWr.m.c.0.8