Task Configuration
The speed of the serial interfaces must be considered for the task configuration (see the section on Supported Hardware and the Communication Principle).
For example, in order that, with 9600 bps at the serial bus terminal, the data can all actually be processed at this speed, the associated communication block must be active at least once per millisecond. The task that operates the function block must have a correspondingly fast setting. The simplest case is when the entire PLC program runs in this fast task. If the task is set slower, then as long as the interface operates with a hardware handshake, the communication will function at reduced speed. Without handshake, data to be received can be lost.
Notice | |
Data loss possible When using KL6xxx Bus Terminals on BKxxxx Bus Couplers, please note that the K-bus update time must be below the cycle time of the task. The K-bus update time can be read in the TwinCAT System Manager after clicking on the bus coupler below the I/O configuration. A reserve of 10 % to 20 % should be taken into account. If there are many bus terminals on one bus coupler, the cycle time of the task may have to be set to at least 2 ms. |