Festo Электромотор MTR-DCI - Manual (Page 179)

5. Commissioning
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Festo P.BE-MTR-DCI-DN-EN en 1209a
5.7.3 Rules for request-response processing
Rules Description
1 If the master sends the identifier for “No request”, the MTR-DCI replies with the
response identifier for “No response”.
2 A request or response telegram always refers to a single parameter.
3 The master must continue to send a request until it receives the appropriate response
from the MTR-DCI.
4 The master recognizes the response to the request placed:
– by evaluating the response identifier,
– by evaluating the parameter number (PNU),
– if applicable, by evaluating the subindex (IND),
– If applicable, by evaluating the parameter value.
5 The MTR-DCI keeps providing the response until the master sends a new request.
6 a) A write request will only be carried out once by the MTR-DCI, even with cyclical repeti-
tion of the same request.
b) Between two consecutive requests with the same request identifier (AK), parameter
number (PNU) and subindex (IND), the request identifier 0 (no request) must be sent
and the master must wait for the response identifier 0 (no response). This is to ensure
that an “old” response is not interpreted as a “new” response.
Tab. 5/6: Rules for request-response processing