一块6ES7 443-5DX02-0XE0 V3.0，用了较多的FC5通讯。改造前（分别与16个PLC站有SEND/RECV通讯，但数据交换量较小），改造后增加了一个PLC站的通讯，但数据量较大（近200个BYTE）目前常出现80A4H故障。HELP中解释为：
The communication bus connection between the CPU and CP is not established. (with newer CPU versions) The reason may be, for example:
No connection configuration; Maximum number of CPs that can be operated at one time has been exceeded (for more information, refer to the CP manual).
但CP重启后一段时间正常，请问是因为通讯连接数太多的原因吗？应该怎么解决较好？