User Manual of EM730 Series Inverter As shown in Table 12-30, EM730 series products mainly involve common function codes . For example, 0x03: function code used to read multiple registers or status words, 0x06 : function code used to write a single register or command, 0x10: function code used to write multiple registers or commands, and 0x08: function code for diagnosis. In addition, for some specific functions, such as register writing (RAM) without EEPROM storage, the user-defined function codes include 0x41: function code used to write a single register or command (without saving), and 0x42: function code used to write multiple registers or commands (without saving).
When the abnormal valid data is received from a device, a related abnormality message will be returned (see 11.3.7 Exception response ). The abnormality function code is defined to distinguish the abnormal data from normal communication data. Corresponding to the normal request function code, the abnormality function code = request function code + 0x80 . Table 12- 30 Function Code Definitions of EM730 series Product PDU parts are detailed in the following sections, depending on various functions. 1.1.1.1 0x03:
function code used to read multiple registers or status words In the remote terminal unit, this function code is used to read the content in the continuous block of the holding register. The request PDU describes the starting register address and the number of registers. 370 Function code Abnormality function code Function 03 83 This function code is used to read multiple registers or status words. 41 C1 This function code is used to write a single register or command without saving. 42 C2 This function code is used to write multiple registers or commands without saving. 08 88 This function code is used for diagnosis. 06 86 This function code is used to write a single register or command.
10 90 This function code is used to write multiple registers or commands.