ISPSoft User Manual 3.4.2.2 Option - COM Port Setting AHxxEMC is equipped with 2 COM ports. Users could set COM1 and COM2 parameters individually by clicking COM Port 1 Setting or COM Port 2 Setting under COM Port Setting. COM1 is for uploading and downloading; COM2 is for Data Exchange. The setting items are same for the two COM ports. Set the communication protocol of the COM port. Users can set a station address at the communication port. A device on a network can be identified by means of the station address of the device. The station address of a device on a network cannot be the same as the station address of another device on the same network.
If the communication port functions as a slave, and there are other slaves, the station address of the communication port cannot be 0. 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 addresses 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 for sending a command in the box of Times of Auto-retry and set the time interval to retry the sending of a command in the box of Time Interval of Auto-retry when the communication fails. PLC module will make a next connection with the network every the set interval time when the communication fails. 3-202