ISPSoft User Manual 3.3.3 Setting COM Port Parameters When users click COM Port from the main category label and enters the setting page and two COM port is setup for the model type, e.g. AHCPU5xx-RS2. The setting page will have two identical COM port setting section but both are independent from each another. For notes on connecting PLC CPUs through COM ports, please refer to section 2.4.8 for more information. Select types of communication with options including RS232 , RS485 , or RS422 . Select the Baud Rate for the communication speed.
When choosing RS232, the baud rate options include 9600 bps, 19200 bps, 38400 bps, 57600 bps and 115200 bps; while for RS485 or RS422, the baud rate options include 9600 bps, 19200 bps, 38400 bps, 57600 bps, 115200 bps, 230400 bps, 460800 bps, or 921600 bps. Setup other communication protocol parameters. When RTU is selected for Transfer Mode , the Data Length is limited to choosing 8 bit. Setup COM Port station address for device identification during connection, while station address on the same network is not allowed to be repeated, the setting range is 0 ~ 247.
When the port is referred to as a slave and there are other slaves connected, the port station address cannot be set as 0 because it is defined as broadcast communication under the communication protocol. However, when the Master assigns data transfer to Slave station address 0, this means the data packets are transferred to all slave stations regardless of the station address. When communication fails, the PLC CPU will retry to connect. Users can setup the times of auto-retry within the range of 0~20. Setup the time interval for auto-retry once communication fails.
When PLC CPU retries to connect due to communication failure, users need to setup the interval time to start the next connection. The setting range is 100~65535 ms. 3-170