The control system of mould level is crucial to improve the slab quality in the continuous casting process , pid controller is used in the traditional mould level control , and it has some defaults , such as : at the start - up or finishing period of casting or during the changeover of tundish , pid control has a bad effect , its overshoot is large and its transient time is long ; the erosion of the tundish stopper and the submersed nozzles lead to the accuracy of control become bad ; the abrupt falloff of block in the submersed nozzles makes the level acutely fluctuate , and pid control can not overcome the disturbances resulted from the change of casting speed 结晶器液位控制系统是提高连铸产品质量的关键环节，传统的连铸机液位控制方法采用常规的pid控制，存在如下不足：开始、结束浇注和换中间罐浇注时，控制效果差，超调量大，过渡时间长；塞棒头和浸入式水口被腐蚀后引起控制精度差；浸入式水口堵塞物的突然脱落所引起的液位剧烈波动；无法克服拉速波动引起的扰动。
Such an agreement would need to achieve four things : fix a realistic new overall ceiling on opec ' s annual production ( which means 16 million barrels a day or less ) ; be sufficiently flexible to allow output to adjust to the sharp seasonal swings in world oil demand ; see that individual countries ' production quotas are both observed and effectively policed and look like lasting whatever happens to non - opec output 这样一个协议应当解决四个方面的问题：一是，从总体上为欧佩克制定一个新的、切实的年度产量上限（意味着每天1600万桶或更少） ；二是，在世界石油需求季节性剧烈波动面前给予充分的灵活性，允许对产量进行调整；三是，确保每个国家均按照配额生产并且得到有效的监控；四是，不论非欧佩克成员国的石油输出如何变化，恒守自己的原则。
