Detector Overview

This screen is used to access and control the four sweep detectors. For each detector the following controls and indicators are shown here (each PV is prefixed with $(device):$(axis) and n runs from 0 to 4):

PV	Description
`:DET:n:ENABLE_S`	Each detector can be enabled or disabled. Normally the only reason to disable detectors would be so that the entire detector memory is available for a very long experiment.
`:DET:n:SCALING_S`	If the sweep is configured for a very long dwell with a high input level then it is possible for the detector to overflow; this control can be used for a further 8 bits of dynamic range.
`:DET:n:COUNT`	This PV indicates how many bunches are being captured by this detector.
`:DET:n:MAX_POWER`	This PV indicates how much dynamic range is available in the detector: if this approaches 0dB then `:DET:n:SCALING_S` may need to be set to -48dB.
`:DET:n:OUT_OVF`	This PV will indicate an error if the last detector capture generated an overflow.

For each detector buttons link to two screens:

Title	Link	Description
Waveforms	Detector Waveforms	Screens for viewing waveforms captured by the detector.
Bunches	Detector Bunch Enables	Configuration screen for editing `:DET:n:BUNCHES_S`.

The setup section of this screen provides the following controls and indicators:

Title PV Description

Source

:DET:SELECT_S

The detector can be used to select one of the following sources:

Source	Description
ADC	In this case the ADC data is passed through to the detector. Typically this doesn't work too well because the fill pattern is inclined to leak through the detector and can interfere with the measurement.
FIR	Here the data being used for feedback can also be passed to the detector. In this case the fill pattern is rejected, but it is difficult to accurately compensate for the phase delay. In this case we are directly measuring the action of the FIR on the machine.
ADC no fill	Here the fill reject filter is applied to the ADC data.

FIR delay :DET:FIR_DELAY_S This can be set to the group delay of the FIR filter so that this delay is compensated for in the detector. However, we have discovered at DLS that setting this to anything other than 0 is confusing.

ADC no fill length :ADC:REJECT_COUNT_S This is a copy of the fill reject length control on the ADC Setup page.

Captured :DET:SAMPLES This records the number of samples captured in the last sweep.

Underrun :DET:UNDERRUN This should never indicate anything other than "Ok", an error here indicates a worrying internal FPGA problem, or possibly an unreasonably small bunch count.

Waveforms :DET:FILL_WAVEFORM_S This is a fudge to help EDM, and should otherwise be set to "Truncated". This will probably be deleted.

Note that 8M (8388608) samples of detector memory are available for capture, but if all four detectors are enabled then only 2M samples per detector are available. Also note that if more samples are captured than will fit into memory then the early samples will be silently overwritten and there will be no warning indication.

On the bottom right two buttons link to related screens:

Title	Link	Description
Tune	Tune Fitting Overview	Link to tune fitter. Note that only tune fitting for the first detector is available.
SEQ Trig	Trigger Target Setup	Trigger configuration for sequencer trigger