ISPSoft User Manual 3.1.4.17 Data Exchange On the Data Exchange Tab, you can set up data exchange for COM communication, Ehternet communication and Function Card. Click Add and then Edit or double-click the data exchange table to open the editing page. Local Device Setting Tick the option Enable for data exchange to start. You can set the shortest update cycle and connection timeout time in ms. If for a period of time that you have set, there is no response from the target device, this is considered as a timeout. If you tick the option Support Read/Write Synchronization (Function Code:
0x17) , the master PLC CPU can use MODBUS function code to complete read and write synchronization at one operation. However you need to make sure all the devices support MODBUS function codes; otherwise, the slaves devices may NOT recognize the function code and fail to complete read/write synchronization. 3-114