Considerations For Using Transmission Control Functions - Mitsubishi Electric MELSEC iQ-R Series User Manual

11.3
Considerations for Using Transmission Control
Functions
The following describes the considerations for using the transmission control function of C24.
Agreement between target device and CPU module
Determine the following between the target device and the CPU module.
• Whether or not the transmission control function is to be used. When it is used, which control is to be used for data
communications.
• Control timing
• DC1 to DC4 codes when DC code control is performed
(The DC1 to DC4 codes to be used can be arbitrarily changed.)
Conditions to use the transmission control function
• DTR/DSR control and DC code control cannot be used at the same time.
• When using DTR/DSR control, connect the ER (DTR) and DR (DSR) signals on the C24 side to the target device.
Transmission control function setting
Set the transmission control function that can control the target interface.
If a function that cannot control the target interface is set, the set contents are invalid.
Setting of transmission control function during interlink operation
When the two interfaces of C24 is used as interlink operation, set the transmission control function to either one of interfaces
of which transmission control is required.
Set the other interface to "Do not use transmission control function" (the setting values to directly set to the buffer memory is
0001H).
DC code control
• DC1/DC3 transmission control and DC1/DC3 reception control are possible when full-duplex communications is used to
communicate data between C24 and target devices.
Do not use DC1/DC3 control for half-duplex communications.
• The same data as the DC1 to DC4 codes cannot be included in the user data.
To handle the same data as a DC code as user data, perform any of the following:
Use DTR/DSR control.
Change the DC code. Do not use the transmission control function.
■Remarks
If the user data received from the target device includes the relevant DC code when DC1/DC3 reception control and DC2/DC4
reception control are used, C24 performs the corresponding DC code control.
If the user data transmitted from the CPU module includes a DC code, it is sent unchanged.
Handling of ER (DTR) and DR (DSR) signals when DTR/DSR control is not used
When the DTR/DSR control is not used, C24 handles the ER (DTR) and DR (DSR) signals as described below.
• ER (DTR) signal is always ON.
• The ON/OFF status of DR (DSR) signal is ignored.
11 DATA COMMUNICATIONS USING DC CODE TRANSMISSION CONTROL
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11.3 Considerations for Using Transmission Control Functions