Automatic summarizing of receive data
In serial communication, a data set is usually sent as a contiguous byte stream. There is a pause between two data sets.
On the basis of the pauses, EPP6002 can recognize when a data set begins and when it ends. This enables it to summarize the bytes of a data set and to forward them as contiguous byte stream to the controller.
Functioning
Several bytes received shortly after one another are initially collected in the receive buffer.
If a pause is detected after a byte, the collected receive data are transferred from the receive buffer into the process image. The “Receive Request” bit is inverted in order to show that new receive data exist.
Enabling / disabling
The automatic summarizing of receive data is enabled in the factory setting. It may be useful to disable it if you wish to receive the data sent by an end device as quickly as possible in the controller. Or if the end device sends continuously without pauses.
If the automatic summarizing of receive data is disabled, each byte received is transferred immediately to the process image.
You can disable the automatic summarizing of receive data by setting the following CoE parameters to FALSE:
Channel | CoE object | Parameter | ||
|---|---|---|---|---|
1 | 8000hex | COM Settings Ch.1 | 05hex | Enable transfer rate optimization |
2 | 8010hex | COM Settings Ch.2 | 05hex | Enable transfer rate optimization |
Length of the pause between two data sets
A pause between two data sets must exceed a minimum length in order to be detected as a pause.
From firmware 04: You can set the minimum length of the pause in parameter 80n0:1D “Transfer Rate Optimization Delay Threshold”. Factory setting: 16 bit times.
Up to firmware 03: The minimum length of the pause is 16 bit times.
Calculation: 1 bit time [s] = 1 / data transfer rate