Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
52
Manual, 09/2008, A5E02191071-01
Response message frame
Once the command message frame has been transmitted, the RK 512 waits for a response
message frame from the communication partner within the monitoring time. The duration of
the monitoring time depends by default on the transmission rate 20 s. This monitoring time
can be reduced by setting parameters for the user in the "RK512" dialog of the parameter
assignment interface. When the option "dependent on transmission rate" is selected, the
following maximum waiting times are used for monitoring:
Table 2- 2
Monitoring time dependent on transmission rate for response message frame
Transmission rate
Monitoring time
•
300 baud
10 s
•
600 baud
7 s
•
1200 baud
5 s
•
from 38400 baud
3 s
The "grayed" field "maximum waiting time" is only used to display the monitoring time used
and cannot be edited!
Structure and contents of the response message frame
The response message frame consists of 4 bytes and contains information on the progress
of the request.
Table 2- 3
Structure of response message frame header (RK 512)
Byte
Meaning
1
Message frame ID in response message frames (00H),
in continuation response message frames (FFH)
2
Message frame ID (00H)
3
Displays 00H
4
Error number of the communication partner in the response message frame:
*
00H if transmission was error-free
> 00H error number
* The error number in the response message frame automatically triggers an event number in the
STATUS output of the function blocks.
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