PVs

This page describes the data held by each PV served by this IOC.

BEGINRUNEX

This is used for starting a run.

Setting this PV to 1 triggers an event which firstly starts the hardware by setting the run status register’s lowest bit to 1, then sends a run start to Kafka. If either of those two fail, the put will error.

ENDRUN

This is used for ending a run.

Setting this PV to 1 triggers an event which firstly stops the hardware by setting the run status register’s lowest bit to 0, then sends a run stop to Kafka. If either of those two fail, the put will error.

PAUSERUN

This is used for pausing a run.

Setting this PV to 1 triggers an event which sets the software_vetoes bit 5 to 1.

RESUMERUN

This is used for resuming a run.

Setting this PV to 1 triggers an event which sets the software_vetoes bit 5 to 0.

DAETIMINGSOURCE / DAETIMINGSOURCE:SP

These PVs respectively display the status of and set the streaming control board’s timing source (or frame_sync_select as named by its register) The options are:

• INTERNAL_TEST_CLOCK: The streaming control board uses it’s internal clock to mark the beginning of new frames, without synchronizing with any external signals. This is useful for testing when an external timing source is not present, but is not useful for scientific data collections.

• ISIS: This synchronizes with the ISIS accelerator timing pulse.

• SMP: This synchronizes to an external timing pulse, usually from a chopper.

• UNKNOWN: The timing source is unknown – the hardware is in a strange state.

HWRUNNING

This PV indicates whether the hardware is running or not, as determined by the status register (in particular the 0x20 bit-flag)

RUNNUMBER / IRUNNUMBER

These are the current run number. A run stop increments these. They are read-only from EPICS, but changing the State file can update them.

PERIOD / PERIOD:SP

The current period number. This is 1-indexed, so period 1 here corresponds to period=0 in the underlying data stream.

NUMPERIODS/ NUMPERIODS:MAX / NUMPERIODS:SP

The maximum period number - note that NUMPERIODS:MAX is just an alias to NUMPERIODS

PERIODTYPE / PERIODTYPE:SP

The current period mode to use. Options are: 0/COMPUTER: Let the control PC (IBEX) set the period modes 1/LOOK_UP_TABLE: Internal period card mode, with a look-up table 2/NOT_USED: Periods not used at all 3/EXTERNAL: Use an external signal to the streaming hardware.

VETO:NAMES

Array of veto names, corresponding to the veto bit mask. Note that this is not changeable at runtime and must be set in the program’s configuration file.

VETO:SP

Veto configuration array. This corresponds to the veto names array. The values in this array are 0 for a disabled veto, 1 for a soft veto and 2 for a hard veto. Setting this will write hard vetoes to hardware and then pushes a vc00 blob, containing a bit-wise OR of both soft and hard vetoes into the veto configuration topic.

VETO:HARD

This is a readback for what is currently set on the streaming control board.