User Manual of EM760 High-Performance Inverter The main diagnosis function used by our company is line diagnosis (0000), which is used to test the normal communication between the host and slave. The normal response to a request to return query data is to return the same data. At the sametime, the function codes and sub-function codes are also copied. ● Request PDU ● Response PDU ● Error PDU ● Sub-function code 0000 : return the data transferred in the request data field in the response. All messages should be consistent with the request message. The following table is an example of requesting the remote terminal unit to return query data. The sub-function code 0000 is used.
The returned data is sent in the two-byte data field (0xA537). 259 Function code 1 byte 0x08 Sub-function code 2 bytes 0x0000~0xFFFF Data 2 bytes 0x0000~0xFFFF Function code 1 byte 0x08 Sub-function code 2 bytes 0x0000~0xFFFF Data 2 bytes 0x0000~0xFFFF Error code 1 byte 0x88 Exception code 1 byte See Table 10-4 Sub- function Meaning Data field (request) Data field (response) 0000 Return query data Any Copy request data …
Request Respond Domain name (0x) Domain name (normal) (0x) Domain name (abnormal) (0x) Function 08 Function 08 Function 88 Sub-function code Hi 00 Sub-function code Hi 00 Exception code 03 Sub-function code Lo 00 Sub-function code Lo 00 Data Hi A5 Data Hi A5 Data Lo 37 Data Lo 37