What is Message Body Format?
The request messages transmitted over an explicit messaging connection should conform to the specific format. The following table shows the format of a nonfragmented explicit request.
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|---|---|---|---|---|---|---|---|
| Frag[0] | XID | MAC ID | |||||
| Class ID | |||||||
| Instance ID | |||||||
| Service Data (Optional) | |||||||
Message body format specifies that the Class ID and Instance ID are 8 or 16-bit integers. The following table describes the message body format values.
| Value | Meanings |
|---|---|
| DeviceNet(8/8) | Class ID = 8 bit integer. Instance ID = 8 bit integer. |
| DeviceNet(8/16) | Class ID = 8 bit integer. Instance ID = 16 bit integer. |
| DeviceNet(16/16) | Class ID = 16 bit integer. Instance ID = 16 bit integer. |
| DeviceNet(16/8) | Class ID = 16 bit integer. Instance ID = 8 bit integer. |