Trigger Configuration - DLS-Controls-Private-org/MBF-docs GitHub Wiki

This screen shows the top level status of the global trigger configuration, divided into four major sections described below. All PVs are prefixed with$(device).

Inputs

This section shows the seven possible trigger event sources and their current status (updated at 5Hz), together with some configuration parameters. The blanking input and its configuration are also shown. The following event sources are available.

Title PV Description
SOFT :TRG:SOFT:IN This is a software generated event which is triggered by processing:TRG:SOFT_S
Soft event :TRG:SOFT_S This PV triggers the soft event:TRG:SOFT:IN. The.SCAN field of this record can be set to arrange for regular pulsing of this event.
EXT :TRG:EXT:IN This event is triggered by a rising edge on TTL input #1 of the digital I/O FMC card. This is intended to be connected to the beam event trigger.
PM :TRG:PM:IN This event is triggered by a rising edge on TTL input #2 of the digital I/O FMC card. This is intended to be connected to the beam postmortem event.
ADC0, ADC1 :TRG:ADC0:IN, :TRG:ADC1:IN These events are generated when min/max ADC motion exceeds the configured limit.
$(axis):ADC:EVENT_LIMIT_S This is the configured limit used to generate the ADC trigger events.
SEQ0, SEQ1 :TRG:SEQ0:IN, :TRG:SEQ1:IN These events are generated when the sequencer first enters the configured trigger state. Note that the SEQ1 event is never generated in LMBF mode.
DAC0, DAC1 :TRG:DAC0:IN, :TRG:DAC1:IN These events are generated when min/max DAC motion exceeds the configured limit.
$(axis):SEQ:TRIGGER_S This is the sequencer state which will generate the corresponding SEQ event.

Also the blanking input is shown and can be configured. The blanking event is used to generate a blanking window which is used to ignore disturbances to the beam which would otherwise disrupt measurements or other experiments. The window is used in two places:

  1. Firstly, any trigger target can choose to ignore any trigger event during the blanking window
  2. Secondly, the sequencer and detector can be configured to ignore beam motion measurements during the blanking window.
Title PV Description
BLNK :TRG:BLNK:IN This event is triggered by a rising edge on TTL input #1 of the digital I/O FMC card. This is designed to be connected to an event synchronous with the disturbance to beam position caused by injection.
:TRG:BLANKING_S This configures the duration of the blanking window in turns. The window starts immediately (within one turn) after the BLNK event is seen.

Shared Arming

If it is desirable to trigger multiple targets simultaneously (for example, triggering a simultaneous scan on both axes) then it is necessary to configure both trigger targets to use the same event sources, and to arm them simultaneously. Simultaneous arming is managed by configuring each target for shared arming, and the state of this arming is managed here.

Title PV Description
:TRG:MODE_S This controls whether shared targets are automatically rearmed after completion. The possible settings are "Rearm" and "One Shot".
Arm :TRG:ARM_S This will arm all shared targets, so long as the shared target status is "Idle".
Disarm :TRG:DISARM_S This will disarm all shared targets, but won't stop activity in progress.
:TRG:STATUS This shows the status of the shared targets. Because of interactions between target arming states, the list of possible values is surprisingly complex:
Status Description
Idle All shared targets are idle, shared triggers are ready for arming.
Armed All shared targets are armed and waiting for a trigger event.
Locked At least one shared target is locked waiting for an external readout to complete. On exit from this state triggers will be armed. This is normally a transient state.
Busy Shared targets are idle or busy processing.
Mixed This state indicates that some targets failed to fire together. Typically this indicates that two shared targets are configured with different trigger inputs.
Invalid This state should not occur, it indicates an internal problem with target locking.

| | Shared targets | :TRG:SHARED | This shows a list of all shared targets. |

Targets

For each target there is a link to the Trigger Target Setup page, together with controls for arming triggers for each target, documented on that page. The following trigger targets are defined:

Target Description
SEQ When this target fires the corresponding sequencer will start processing, seeSequencer Setup for details on the behaviour of the sequencer. In LMBF mode only the IQ axis sequencer is provided.
MEM When this target is armed capture to fast memory is started. Capture will be completed when a trigger is seen. Refer to Fast Memory Capture for details.

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