SPA Error Response message
If the SPA Request message is executed incorrectly, error information will be sent to the PLC via an SPA Error Response message. This is structured as follows:
00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 |
|---|---|---|---|---|---|---|---|---|---|---|---|
Status | SPA TID | Index | Subindex | Offset | Error | Error Code | |||||
Low | High | Low | High | LSB LO | LSB HI | MSB LO | MSB HI | ||||
The individual bytes have the following functions:
Byte | Name | Bit width | Function |
|---|---|---|---|
00 | Status | 8 | Status byte. The status byte is structured as follows:
The following supported SPA services are mapped in the status byte:
|
01 | SPA TID | 8 | Smart Parameter Access Transaction Identifier The byte for assigning the SPA Response message to the SPA Request message is assigned by the device and mirrored by the AS-Interface master. The client can determine whether the SPA Request message has been answered based on the SPA TID of the SPA Response message. |
02 – 03 | Index | 16 | Main index of the parameter |
04 | Subindex | 8 | Subindex of the parameter |
05 – 06 | Offset | 16 | Offset |
07 | Error Class | 8 | Error class (see chapter SPA service errors in SPA Error Response messages) |
08 | Error Code | 8 | LSB LO – Low byte of the sub-error code |
09 | 8 | LSB HI – High byte of the sub-error code | |
10 | 8 | MSB LO – Low byte of the error code | |
11 | 8 | MSB HI – High byte of the error code |
