User Manual of EM760 High-Performance Inverter ● Response PDU ● Error PDU Below is an example ofa request to change the main frequency source A (7001H) to “-50.00%”: * This function code cannot be used to change the parameters of the attribute “○” (it cannot be changed during operation). That is, only the parameters of the attribute “●” (it can be changed during operation) can be changed. Otherwise, the error code 1 will be returned. 10.3.3.3 0x42: function code used to write multiple registers or commands (without saving) In the remote terminal unit, this function code is used to write consecutive non-holding register blocks (1 to 16 registers).
The value requested to be written is described in the request data field. The data of each register is divided into two bytes. In the normal response, the function code, starting address and number of registers written will be returned.
● Request PDU N* = number of registers 257 Function code 1 byte 0x41 Address of register 2 bytes 0x0000~0xFFFF Register value 2 bytes 0x0000~0xFFFF Error code 1 byte 0xC1 Exception code 1 byte See Table 6-26 Request Respond Domain name (0x) Domain name (normal) (0x) Domain name (abnormal) (0x) Function 41 Function 41 Function C1 Register address Hi 70 Register address Hi 70 Exception code 03 Register address Lo 01 Register address Lo 01 Register value Hi EC Register value Hi EC Register value Lo 78 Register value Lo 78 Function code 1 byte 0x42 Starting Address 2 bytes 0x0000~0xFFFF Number of registers 2 bytes 1~16 Number of bytes 1 byte 2×N* Register value N*×2 bytes