User`s manual

210
7.3 Precautions when Using the Transmission Control
Functions
The following describes the precautions to be observed when using the Q series C24 transmission control functions.
(1) Agreement between external device and programmable controller CPU
The external device and programmable controller CPU must agree to the following.
• Whether or not a transmission control function is to be used. If a control function is used, which control is to
be used for data communications.
• Control timing.
• DC1 to DC4 codes when DC control is performed. (The DC1 to DC4 codes used can be arbitrarily changed.)
(2) Transmission control function usage conditions
• DTR/DSR control and DC code control cannot be used at the same time. Select one of them using the GX
Configurator-SC registration.
• When using DTR/DSR control, connect the Q series C24 ER (DTR) and DR (DSR) signals to the external
device.
(3) Transmission control function setting
Set a 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.
(4) Setting of transmission control function during linked operation
When the two Q series C24 interfaces are linked ( User's Manual (Basic)), set the transmission control
function of only the interface that must be controlled.
Set the other interface to "Do not use transmission control function" (set value when directly set to the buffer
memory: 0001H).
(5) DC code control
• DC1/DC3 transmission control and DC1/DC3 reception control are possible when full-duplex
communications is used to communicate data between the Q series C24 and external devices. Do not use
DC1/DC3 control with 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, do the following.
• Use DTR/DSR control.
• Change the DC code.
• Do not use the transmission control functions.
If the user data received from the external device includes the relevant DC code when DC1/DC3 reception control and
DC2/DC4 reception control are used, the Q series C24 uses the corresponding DC code control.
If the user data transmitted from the programmable controller CPU includes a DC code, it is sent unchanged.