关于第二个问题，我们实际操作中，一般是每日使用前校准，但是如果出现天平关机的情况，就会在启动后再进行一次校正。不过，这种到底是否是基于科学设计还是仅基于法规要求，确实没有找到足够支持的文件，也在学习中。

1、即使有内部校准功能也要定期用外部砝码去校准并生成校正报告

2、我司对于此规定是在每次称量前进行校准并在使用记录中记录。

每日或每次，为什么你就只看每次呢？每日也行呀

欧洲药典2.1.7 Balances for analytical purposes，日常灵敏度测试接受内置砝码，但应定期使用外部砝码校准。

“In addition to testing weighing instruments with external weights, it is accepted practice to adjust the instruments by means of built-in weights. This makes it possible to reduce the frequency of sensitivity tests with external reference weights. For electronic balances with a built-in weight, daily sensitivity testing with an external reference weight is not considered necessary, but a test with external weights should nevertheless be conducted periodically since it allows detection of any problems with the built-in weights themselves”

USP 1251 也允许部分使用内置砝码。

“A balance check using an external weight helps ensure that the balance meets weighing tolerance requirements. The balance check is performed at appropriate intervals based on applicable standard operating procedures. The frequency of the balance check depends on the risk of the application and the required weighing tolerance. Checks with external weights can be replaced partially using automatic or manually triggered adjustment by means of built-in weights. When analysts perform the balance check with an external weight, the same acceptance criteria may apply as described in the sensitivity test above.”