labview7.1数据采集输出模拟信号问题？？？？

错误如下：

Error -200560     occurred at DAQmx    Wait   Until   Done.vi

Possible reason(s):

Measurements: Wait Until Done did not indicate that the task was done within the specified timeout.

Increase the timeout, check the program, and make sure connections for external timing and triggering are in place.

Task Name: _unnamedTask<12>
好像是时间溢出了，我想让时间循环，使时间不溢出，时间无穷大也不行