There is a summary display available which integrates the information from feedback and fast feedforward. An example is shown in figure 4. It is available from the FFBK SELECT or CANNED PLOTS panel after the scavenger energy loop has been selected.
The bottom-left half of the display graphically depicts the total energy being given to the beam by sectors 17 and 18. This is split into an amount being requested by feedback and an amount being added on by feedforward.
The second bar graph from the left (labeled ``Feedback energy") shows the amount of energy that feedback is requesting. The bar runs from the minimum energy the sectors can contribute (both of them back-phased) to the maximum energy they can contribute (both at zero phase). Also marked is the maximum energy that can be contributed while maintaining the proper BNS phase (-17 degrees at the moment). The mark labeled ``Max. Fbck E" indicates the maximum energy that feedback will ever try to contribute. It is placed down from ``Energy w/BNS" by the headroom that feedback leaves for fast feedforward. Finally, the ``Fbck E Req." shows the amount of energy that feedback is presently requesting the sectors to contribute to the beam.
The left-most bar graph (labeled ``Feedforward + Feedback Energy)" shows the total amount of energy requested by feedforward and feedback together. This bar starts from the ``Fbck E Req." level so that the distance between the between the bottom and the marked total request is feedforward's energy request.
For each quantity both the request and the hardware readback are given. If both fast feedforward and feedback are on, then the readback should agree with the request unless the hardware is broken.
The bottom-right of the display depicts the sector 17 and 18 phase settings. Its format is similar to the graphical energy display.
The top half of the display gives information on the setup of the
systems. This includes the states of feedback and feedforward (on
or off) and the values of various gains which have been described
above. Note that the ``state" column on the right hand side just gives
a crude indication of whether part of feedforward has been turned off
by setting its gain to something small (
). To check the gains
more accurately than this, you must compare them to the values in the gold
configuration for the appropriate AMPLs.
A more detailed explanation of the display is available in the online
help.
