Is there a procedure for testing the photocell in the CL17 analyser?

Document ID

Document ID TE5839

Published Date

Published Date 18/06/2019
Question
Is there a procedure for testing the photocell in the CL17 analyser?
Summary
Testing the CL17 analyser photocell.
Answer
The photocell in the CL17 colorimeter can be easily tested with a digital multimeter (DMM).  The DMM must have a very high input impedance – greater than approximately 100 M W – to properly perform this test. 
 
The photocell provides a voltage output proportional to the amount of light striking it.  In complete darkness, the output is zero; when the photocell is saturated in bright light, the maximum output is approximately 300 mV. 
 
The photocell assembly is Product # 47229-00.  This part is used in the 47235-00 colorimeter assembly.  Replacement photocells are not available for the old 44217-00 colorimeter. 
 
 
 
 
Photocell in full overhead light –
Maximum output is approximately 300 mV.
 
 
 
 
Photocell covered to block light –
Output drops to zero.