Trigger Configuration
- Michael Abbott
- Benoît Roche
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. |
$(axis):SEQ:TRIGGER_S | This is the sequencer state which will generate the corresponding SEQ event. | |
| DAC0, DAC1 | :TRG:DAC0:IN, :TRG:DAC1:IN | These events are generated when min/max DAC motion exceeds the configured limit. |
$(axis):DAC:EVENT_LIMIT_S | This is the configured limit used to generate the DAC trigger events. |
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:
- Firstly, any trigger target can choose to ignore any trigger event during the blanking window
- 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 #3 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:
| |||||||||||||||
| 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, see Sequencer 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. |