Delta AH500 Hardware Operation Manual page 384

A H 5 0 0 H a r d w a r e a n d O p e r a t i o n M a n u a l
8.1.3.4 COM Port
If the CPU module is equipped with two communication ports, there are two setting areas for the two
communication ports, and the two communication ports are set individually.

You can select RS232, RS485, or RS422 in the Communication Type drop-down list box. For AH560
Series PLC, only RS232 and RS485 are supported.

Users can set the communication protocol parameters. If the RTU option button is selected in the Transfer
Mode section, the 8 bit option button in the Data Length section is automatically selected.

Users can set a station address. A device on a network can be identified by the station address of the
device. The station address of a device on a network can not be the same as the station address of
another device on the same network. The station address of a device must be in the range of 0 to 247.
If the communication port functions as a slave, and there are other slaves, the station address of the
communication port can not be 0, since station address 0 has the meaning of broadcasting to all slaves in
a communication protocol. If a master specifies in a data packet that data must be sent to station address
0, the data will be sent to all slaves. No matter what station address of these slaves are, these slaves will
receive the data packet.

If the sending of a command fails, the CPU module will retry the sending of the command. Users can set
the number of times the sending of a command is retired in this box. The number of times the sending of a
command is retired must be in the range of 0 to 20.

Users can set an interval of retrying the sending of a command. If the sending of a command fails, the
CPU module will retry the sending of the command every specific period of time. The interval of retrying
the sending of a command must be in the range of 100 milliseconds to 65535 milliseconds.
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