1，因为 CALL "CNT2_CTR" 之后， "CNT2_CTR"程序体内可能打开其他DB，所以此后必须重新 OPN DB [#cnt2_db] ，指向所操作的DB。

2，SAVE saves the RLO into the BR bit. The first check bit /FC is not reset. For this reason, the status of the BR bit is included in the AND logic operation in the next network.

The use of SAVE and a subsequent query of the BR bit in the same block or in secondary blocks is not recommended because the BR bit can be changed by numerous instructions between the two. It makes sense to use the SAVE instruction before exiting a block because this sets the ENO output (= BR bit) to the value of the RLO bit and you can then add error handling of the block to this.