The 68951 Digital ExposureSystem is a light intensity controller and digital timer in one package. It maintains a constant light level and allows preset timed or dosage based exposure control. The 68951 is made up of a light sensing head, a controller, and a fiber optic probe. The controller may be controlled via a PC through an RS-232 interface. The silicon based light sensor monitors part of the light source output (via the fiber probe), and the controller constantly compares the recorded signal to the set level and changes the power supply output accordingly to keep the measured signal at this user-deifned level. Automatic detector gain setting allows the unit to work with 300 to 1600 W solar simulator models.

The 68951 also allows for timed exposures. The 68951 is capable of exposure times from 10 ms to 9999 hours, in increments as short as 10 ms. However, the mechanical response time of the shutter in our solar simulators limits the minimum exposure time to 100 ms, and the shortest interval between exposures to 80 ms. For those instances when a timed exposure is not sufficient, the auto-dose mode can be implemented to keep the shutter open until the total flux equals a user set value.

The system consists of the following:

68951数字曝光系统是一个光强控制器和数字定时器在一个包。它保持一个恒定的光水平，并允许预先设定的时间或剂量的曝光控制。68951由光敏头、控制器和光纤探头组成。控制器可通过PC机通过RS-232接口进行控制。基于硅的光传感器监控部分光源输出(通过光纤探头)，控制器不断地将记录的信号与设置的电平进行比较，并相应地改变电源输出，使测量的信号保持在用户指定的电平上。自动探测器增益设置允许单位工作与300到1600 W太阳模拟器模型。

68951还允许定时曝光。68951的曝光时间从10毫秒到9999小时不等，每隔10毫秒就会增加一次。然而，在我们的太阳能模拟器中，快门的机械响应时间限制了最低曝光时间为100毫秒，最短曝光间隔为80毫秒。对于那些时间曝光不足的情况，可以实现自动剂量模式以保持快门打开，直到总通量等于用户设置的值。

系统由以下部分组成:

68945数字曝光控制器

71582 SI, UV增强冷却探测器头

70018 BNC电缆

70062温度控制电缆

70043特种连接器电缆

68957光纤探头