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Message ID: 87     Entry time: Sat Jul 31 11:54:20 2010
Author: Aidan 
Type: Computing 
Category: SLED 
Subject: SLED Test Day 5 - Re-tuned current set-point control voltage 

Main Points

  • Re-set SLED current set-point control voltage to 0.111V
  • SLED current set-point voltage drops by about 5mV when the SLED is dis-engaged
  • Resetting was around 11:45AM PDT 31st-Jul-2010

I turned off the SLED for 10s and reset the current set-point voltage (read using a mutlimeter and probing a couple of pins at the back of the driver board). The initial voltage when the test started on Monday was 0.111V when the SLED was engaged. This drooped to 0.109V over the week and there was a corresponding (but possible not resulting) drop in on-board photo-diode voltage. When the SLED was disengaged the set-point current control voltage dropped to 0.104V. I turned the LP pot on the front of the SLED driver board until the multimeter read 0.106V and re-engaged the SLED. The curernt set-point voltage then read 0.111V, occasionally popping up to 0.112V for a moment or two.

The DC Power Supply to the SLED reads 8.9V with 0.26A current being drawn.

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