Example for CTT2 Read Request/Response service – Determining the device ID
The CTT2 Read Request/Response service can be used to query the device ID, such as vendor ID and device ID, in order to identify the AS-Interface device.
The following figure shows the general process:
[1] | PLC |
[2] | AS‑Interface master |
[3] | B device |
[4] | Read Request message – This is sent to the B device when the device ID is requested. |
[5] | Cyclic data exchange |
[6] | Acyclic parameter communication from the AS-Interface master to the B device consisting of 3 bytes CTT2 service. |
[7] | Read Response message – This is sent to the AS-Interface master after the CTT2 service has been processed. |
[8] | Acyclic parameter communication from the B device to the AS-Interface master consisting of:
|
[9] | Read Response message – Contains the result of the parameter access. |
Additional information
