In function model "Standard", Automation Runtime takes over Flatstream communication for transferring characteristic values. The user is automatically provided with all characteristic values, already properly scaled. As a result, the registers for the characteristic value Flatstream are not shown in the I/O mapping in Function model 0 - Standard.

When using Flatstream in Function model 0 - Standard and Function model 1 - Fast master, the following should be noted:

•The maximum bus cycle time should not exceed 10 ms.

•The task cycle should either be the same speed and synchronous to the module's bus or faster.

在 "Standard"（标准化）模型中, Automation Runtime 接管了用于传输特征值的 Flatstream 通信。自动向用户提供已经适当缩放的所有特征值。因此，特征值Flatstream的寄存器没有显示在Function model 0 - Standard功能模型的 I/O mapping 中。

Function model 0 - Standard 和 Function model 1 - Fast master 中使用 Flatstream 时，应注意以下几点：

•总线最大循环时间（cycle time）不应超过10毫秒。

•任务（Task）循环周期应该与模块的总线速度相同并同步，或者更快。

Bus cycle time

总线循环时间

Since the characteristic values are transferred over the Flatstream, a maximum bus cycle time of 10 ms should not be exceeded. Otherwise, the data calculated by the module every 300 ms cannot be fully transferred on the bus. If the current transfer is not completed when new characteristic values become available, then they will be discarded. A cycle time of ≤10 ms is therefore required in order to ensure seamless measurements.

由于特征值是通过 Flatstream 传输的，因此总线最大的循环时间不应超过10ms。否则，模块每 300ms 计算的数据不能在总线上完整传输。如果当新的特征值出现时，而当前的传输还没有完成，那么它们将被丢弃。因此要求循环时间 ≤10 ms，以确保无缝测量。

Task cycle time

任务循环时间

It is important to note that the module normally changes the values in the Flatstream in every X2X Link cycle. To optimize performance and avoid missing any values in the task, it is important to select a task cycle that is either the same speed and synchronous to the module's bus or faster. This also applies to fieldbus connections between the CPU and bus controller. If this is not possible for some reason, it is also possible to change the ForwardDelay of the Flatstream (see The Forward function on the X20CM4810).

需要注意的是，模块通常会在每个X2X链路周期中更改Flatstream中的值。为了优化性能并避免在任务中丢失任何值，重要的是选择一个速度相同且与模块总线同步或更快的任务周期。这也适用于CPU和总线控制器之间的现场总线连接。如果由于某种原因无法实现，也可以更改 Flatstream 的ForwardDelay（请参阅。The Forward function on the X20CM4810 上的 Forward 功能）

Topics in this section:

本节中的主题：

• Registers for the characteristic value Flatstream	• Flatstream 特征值的寄存器
• Structure of the characteristic value Flatstream	• Flatstream 特征值的结构