如何在T-CPU中激活掛在DP總線的第二套編碼器作為測量系編碼器

　　圖3

　　7．完成編碼器參數設定后，保存編譯。

　　三、關于"MC_ChangeDataset"功能塊的應用體會

　　1．編碼器變換發生的時間，有四種選擇。

　　①NEVER:

　　Data record changeover not allowed. "MC_ChangeDataset" is terminated with

　　error (ErrorID = 8045).

　　②IN_POSITION:

　　(Default setting in S7T Config after an axis was inserted)

　　Changeover of the data record takes place when the active motion has

　　reached the programmed positioning window. Position control must be enabled

　　at the axis. If the axis is disabled, the data record is changed over immediately

　　after the axis is enabled.

　　The data records are not changed at following axes which are in synchronism

　　(InSync = TRUE or InGear = TRUE) Use the value IN_STANDSTILL or

　　IMMEDIATELY for following axes

　　③IN_STANDSTILL:

　　The data record is changed over when the standstill signal of the relevant axis

　　is output The data record is changed immediately after the axis has stopped

　　④?IMMEDIATELY:

　　The data record is changed over immediately

　　這四種方式可以通過軸屬性下的專家參數設定，也可以通過"MC_WriteParameter"功能塊切換，主要根據工藝。默認為"IN_POSITION:"，圖4給出在專家參數下設定為"IMMEDIATELY"，主要為調試方便。 　　圖4.1 　　圖4.2

　　2．功能塊執行的有效期

　　當測量從第一套編碼器切換到第二套編碼器后，不管"MC_ChangeDataset"功能塊中的"Execute"信號處于什么狀態，上次執行的切換一直有效。