Placeholder for Tune PLL Debug screen
This screen can be used to monitor the detailed behaviour of the detector on a sample by sample basis, using the same pacing as the :PLL:NCO:OFFSETWF waveform readback. Note however that this data is also available when the controller is not running.
On this screen we see the IQ values read from the detector and the corresponding magnitude and angle values, together with a handful of extra controls for specialised use. All PVs are prefixed with $(device):$(axis).
| Name | PV | Description |
|---|---|---|
| Magnitude | :PLL:DEBUG:MAG | This shows the magnitude of each sample read from the detector. |
| Angle (deg) | :PLL:DEBUG:ANGLE | This shows the phase angle in degrees for each detector sample. |
| I/Q |
| This shows the raw IQ values for each detector sample. |
| Debug FIFO readout overrun | :PLL:DEBUG:FIFO_OVF | If the dwell time is too small it is possible for the readout buffer to overflow, in which case this PV will indicate an error. |
| Detector overflow | :PLL:STA:DET_OVF | This is a copy of the detector overflow status from Tune PLL. |
| Enable | :PLL:DEBUG:ENABLE_S | The detector readout can be turned on and off. To save processing resources, this should probably normally left "Off". |
| Compensate | :PLL:DEBUG:COMPENSATE_S | Normally all reported IQ readings are phase compensated for the delay mismatch between the excitation from the NCO and the captured data. This delay comprises both the single revolution delay involved in driving the signal onto the synchrotron, together with some skew within the FPGA. Setting this PV to "Raw" allows the uncompensated IQ readings to be seen. This is not normally useful. |
| Select IQ or CORDIC | :PLL:DEBUG:SELECT_S | Normally the magnitude and angle readings shown here are computed from the detector IQ readings, and the CORDIC conversion used by the FPGA to drive the feedback controller is hidden. Setting this to "CORDIC" means that instead the magnitude and angle values are those computed on the FPGA (and the IQ readings are back converted). This is also normally not useful, but can be useful to see the phase resolution. |