ABB 57120001-FG DSAO 130可控硅模块
读回命令读回命令允许用户查看定时器计数、定时器模式、OUT引脚的当前状态和所选定时器的加载标志。与控制字一样，回读命令被写入控制字寄存器，格式如表4-7和4-8所示。该命令适用于通过设置相应位Cnt2、Cnt1、Cnt0=1而选择的计时器。通过设置计数位=0并选择计时器，可使用读回命令来锁存多个计时器计数。这与使用多个定时器锁存命令相同。同样，每个计时器的锁存计数将被保持，直到其被读取。读回命令还可用于通过设置状态位=0并选择计时器来锁定计时器状态。计时器的状态可通过读取该计时器来访问（见第55页表4-1）。如果发出多个计时器状态读回命令而未读取状态，则将忽略除第一个命令之外的所有命令。计时器状态字节的格式如表4-9和4-10所示。
Read-Back Command The Read-Back Command allows the user to view the Timer Count, the Timer Mode, the current state of the OUT pin, and the Load Flag of the selected Timer. Like a Control Word, the Read-Back Command is written into the Control Word Register and has the format shown in Tables 4-7 and 4-8. The Command applies to the Timer(s) selected by setting the corresponding bits Cnt2, Cnt1, Cnt0 = 1.The Read-Back Command can be used to latch several timer counts by setting the Count bit = 0 and selecting the Timers. This is the same as using multiple Timer Latch Commands. Again each Timer’s latched count will be held until it is read. The Read-Back command can also be used to latch the timer status by setting the Status bit = 0 and selecting the Timers. Status of a Timer is accessed by a read from that Timer (see Table 4-1 on page 55). If more than one Timer Status Read-Back command is issued without reading the status, all but the first are ignored. The format of the Timer Status byte is shown in Tables 4-9 and 4-10.
