Using Cyclic Data Exchange¶
The sub modules Channel 1 and Channel 2 can be used to transfer I/O data cyclically between the Processor Module and the CM574-RS Communication Module. Input and Output Modules can be attached to these sub modules. The procedure corresponds to that of the hardware inputs and outputs, as described in chapter “2.3 Processing of Inputs and Outputs in the Multitasking System” in AC500 System Technology Documentation.
Per channel, a maximum of 500 Bytes of I/O data can be exchanged.
A maximum of 32 sub modules can be attached. There is no automatic monitoring of the 500 bytes being exceeded. For this reason, it needs to be checked whether the last module exceeds the highest permissible input or output address. These addresses are:
| Channel | Communication Module inputs in slot x | Communication Module outputs in slot x | ||||
|---|---|---|---|---|---|---|
| %IBx.y | %IWx.y | %IDx.y | %QBx.y | %QWx.y | %QDx.y | |
| Channel 1 | %IBx.499 | %IWx.249 | %IDx.124 | %QBx.499 | %QWx.249 | %QDx.124 |
| Channel 2 | %IBx.999 | %IWx.499 | %IDx.249 | %QBx.999 | %QWx.499 | %QDx.249 |
Note
In the project of the CM574-RS, the same I/O Modules have to be configured for data exchange with the Processor Module.