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Reports until 19:47, Friday 22 March 2019
H1 TCS (TCS)
daniel.vander-hyde@LIGO.ORG - posted 19:47, Friday 22 March 2019 (47770)
Some instructions on using the RH guardian

Today I updated the RH guardian. This post is to provide a summary on how to use it: 

The default state is the NOMINAL state. This state acts as if there is no guardian present so you should have the ability to manually change the power to each of the segments. 

Making a change with the inverse RH filter 

  1. If you want to make a RH power change with the inverse filter you can switch to FILTER_RH_INPUT from NOMINAL.
    • The guardian must go through RESET state first to appropriately set a necessary DC RH power offset. Before today's update you had to do this manually because I set an edge from NOMINAL to FILTER_RH_INPUT that shouldn't have been there. It should now go through RESET if you request FILTER_RH_INPUT from NOMINAL. 
  2. To enter the power change you must put it in the "Filter input [W]" input (please see blue circled area for explicit location on RH medm).
    • You have to type in the box before you can move around the cursor to change the value.
    • Total delivered power to the optic will be double the entered amount (because of the two segments). 
    • 1W of added RH power (.5W to each segment) corresponds to a -18 µdiopter double pass lens
  3. You can make a series of changes to the RH power that should converge to the requested lens within 3 hours of the last change. I wouldn't suggest making too many changes (more than three within a 3 hour period) since I'm not sure if the inverse filter output from many stacked changes will be interpreted well by the plant. Once you are happy with where you are at you should leave the RH guardian state in FILTER_RH_INPUT for at least 2 days before returning to NOMINAL.
  4. When waiting for this two day period, I would suggest being semi-aware of any restarts to the front end (will reset inverse filter) or guardian machines (will reset the guardian state back to NOMINAL) since this has the potential to throw off your RH change. I'll be thinking of some safety that can be implemented in the case when this does happen. 
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