Laser-Scanning ASI Sequence

[AdvancedImagingUTSW]

@jondaniels - For your reference, here is our current workflow.

PLC Control Loop (2).pdf

We hope to get this working with a galvo-based laser-scanning system for @bscott711. One possibility is to get a TTL out from the tggalvo for when it has hit its landmark, which is similar to when we get a trigger from the stage. Most people use some version of the mmspim firmware. Need to decide if the heartbeat is coming from the mmspim card, or from the stages. If from the former, then there are pulses on the backplane to trigger the tgplc.

Brandon's current system: A TG-1000-16 controller operating on micro-manager.

• TIG/COM
• 1:X/Y
• 2:Z (with CRISP)
• 3:ABCD (Only have AB connected for single galvo, and only one is needed, forget off top of my head which letter)
• 4:P (with CRISP, O3 is connected on this)
• 5:F/G (Currently only use F, acts as a tilt adjustment stage)
• 6:E (1 cam out, 3 global shutter, 5-8 lasers)

[AdvancedImagingUTSW]

Can our cell 7 trigger a galvo SPIM to do a step? If so, we may be set.

@bls337 just looping you in as well...

[AdvancedImagingUTSW]

Integrating TG‑1000 Galvo SPIM with PLC‑Triggered Workflow

This discussion focuses on implementing hardware-triggered galvo stepping within a TG-1000-16 (TIGER) controller running Micro-Manager, in order to integrate a galvo-based SPIM scanning system into an existing PLC-driven acquisition workflow.

Existing System Configuration

Brandon’s current TIGER configuration includes multiple axis cards:

Slot	Function
1	X/Y stages
2	Z stage (with CRISP autofocus)
3	ABCD card (A/B used for single galvo)
4	P card (CRISP, O3 connected)
5	F/G card (F used as tilt stage)
6	E card (camera outputs, global shutter, laser control)

The intended workflow is for a PLC cell trigger (e.g., cell 7) to generate a TTL pulse that causes the galvo to perform a relative step, similar to how stage stepping is triggered in the current system.

---

Key Implementation Details

1. TTL Triggering via Backplane

The TGDAC4 / TGGALVO card does not currently route its TTL input/output to the TIGER backplane by default.

To enable PLC-driven triggers:

• The card must be physically modified.
• A TTL input must be soldered from the GALVO card to a backplane TTL line.

Recommended backplane lines:

Backplane Line	Recommended Use
TTL4	Preferred
TTL6	Preferred
TTL5	Avoid (used for scan sync)

This modification allows backplane signals (e.g., PLC outputs) to trigger the galvo card.

ASI provided a 2-page modification document describing the procedure. The work must be performed at a static-dissipative workstation.

If users are uncomfortable performing the modification, ASI can perform the modification via RMA at no cost other than shipping.

---

2. Firmware Changes

ASI supplied a modified firmware build:

GALVO_SPIM__ABCD

Changes include:

IN0_INTERRUPT

This module enables hardware interrupt triggering from a TTL input.

One firmware change was required:

• RT Z command support was commented out when adding IN0_INTERRUPT.

This only affects:

• array module
• ring buffer module

These modules are not required for the galvo SPIM stepping workflow, so this change should not impact functionality.

---

3. Operating Mode for Triggered Galvo Steps

There is no explicit "arming" routine for the galvo.

Instead, the galvo card should be placed in:

<addr> TTL X=2

This mode causes the card to:

Perform a repeated relative move whenever a TTL trigger is received.

Thus the workflow becomes:

TTL pulse → relative galvo step

Documentation:
https://asiimaging.com/docs/commands/rbmode

---

4. Testing Without Hardware Modification

Before modifying the hardware, triggering behavior can be simulated using the RM command:

RM

This simulates a TTL input pulse, allowing validation of the step behavior without a physical trigger.

---

5. Optional Settling Delay

If needed, a delay can be inserted between steps using:

WAIT

Documentation:
https://asiimaging.com/docs/commands/wait

This can help ensure galvo settling time before acquisition.

---

Proposed Control Flow

Target implementation:

PLC trigger
     ↓
Backplane TTL line (TTL4 or TTL6)
     ↓
TGGALVO card TTL input
     ↓
TTL mode (X=2)
     ↓
Relative galvo step

Optionally:

TTL step
   ↓
WAIT delay
   ↓
camera / acquisition trigger

---

Remaining Integration Questions

1. Which device should generate the heartbeat trigger?

   • mmSPIM card
   • stage controller

2. Which backplane TTL lines are available in the current TIGER configuration?

3. Whether a settling delay is required after each galvo step.

[bls337]

1. To replicate your current PLC control loop, I believe you would use the mmSPIM card to receive and send the TTL pulses.

2. I think TTL4 and TTL6 are the best bets, especially since the next card revision will have a jumper to route those lines to the backplane. You can email Chris Dax for more details if you're interested.

3. This will mostly require testing on your end to determine.

[jondaniels]

I think TTL7 is a good backplane choice for an input to the card with MM_SPIM firmware (i.e the TGGALVO card or the TGMM4 card).

There are 8 backplane TTL lanes and conceptually any can be used in your "brand new" application. But they have historic usage with the diSPIM and ASI single-objective light sheet system and one of ASI's OEM customers, and so convenience/compatability there is the reason to choose one over the other.

You can see the diSPIM uses at https://asiimaging.com/docs/tiger_programmable_logic_card#dispim_backplane. All but TTL5 and TTL7 are outputs of the usual MM_SPIM card which is the master timekeeper.

[AdvancedImagingUTSW]

Firmware Update

ASI provided an updated firmware build:

GALVO_SPIM__ABCD

Added Module

IN0_INTERRUPT

This module enables hardware interrupt handling from a TTL input, allowing external triggers to initiate galvo motion.

Firmware Changes

To include IN0_INTERRUPT, the following command support was disabled:

RT Z

This command is used only by:

• Array module
• Ring buffer module

These modules are not required for the current galvo stepping workflow, so the change should not impact the intended use.

Documentation:

• https://asiimaging.com/docs/commands/rtime

---

Galvo Triggering Behavior

Trigger Mode

The galvo card should be placed in:

<addr> TTL X=2

In this configuration:

• Each TTL pulse triggers a relative move
• The move repeats for each incoming trigger

Documentation:
https://asiimaging.com/docs/commands/rbmode

---

Testing Without Hardware Modification

Before modifying the GALVO card hardware, trigger behavior can be verified using:

RM

RM simulates a TTL input pulse, allowing validation of repeated relative motion.

Testing confirmed that:

• RM successfully triggers repeated relative moves.

---

Backplane TTL Triggering

The system already uses PLC-generated TTL signals on the TIGER backplane to trigger single-axis waveforms.

Previously observed mapping when using SAM mode 2:

TTL Line	Axes Triggered
TTL1	A, H
TTL3	B, I
TTL5	C, J

The expectation was that the same TTL trigger lines used for remote focus waveform triggering could also trigger the galvo step motion.

However:

• External TTL pulses did not trigger the galvo motion, even though RM worked.

---

Root Cause

The GALVO card cannot respond to backplane TTL signals until the hardware modification is performed.

Specifically:

• The GALVO card's TTL input is not connected to the backplane by default
• The input must be wired to a backplane TTL line

Once wired, a backplane signal going high will trigger the repeated relative move.

---

Additional Configuration Note

When using Single Axis Mode 2, the TTL input mode must be set to:

TTL X=30

This enables the appropriate trigger behavior for single-axis waveform control.

---

Implementation Implication

To enable PLC-triggered galvo stepping:

1. Physically connect the GALVO TTL input to a backplane TTL line
2. Configure the card with:

<addr> TTL X=2

(or TTL X=30 if using SAM mode 2)

3. Each PLC-generated TTL pulse will then trigger the configured galvo move.

[AdvancedImagingUTSW]

Follow-up Discussion: Backplane TTL Triggering via TTL_AUXILIARY Module

Alternative Triggering Approach (No Soldering Required)

ASI indicated that a legacy firmware module called TTL_AUXILIARY may allow backplane TTL signals to be used as trigger inputs without modifying the GALVO card hardware.

This module allows backplane TTL signals to be interpreted as standard TTL input triggers.

Mechanism

The module works by:

1. Selecting which backplane TTL lines should be monitored.
2. Converting rising edges on those lines into a normal TTL input trigger event.

These events then trigger the behavior defined by the card's TTL X mode.

---

Example Configuration

If a PLC generates a trigger on backplane TTL1, the following configuration can allow it to trigger the Single Axis function:

3 TTL T=2
3 TTL R=2
3 TTL X=30

Command Explanation

Command	Purpose
TTL T=<mask>	Bitmask specifying which backplane TTL lines to observe
TTL R=2	Enables backplane-trigger input mode
TTL X=30	Configures TTL input to start the Single Axis function

Example:

TTL T=2

Selects TTL1 because the mask uses the second bit.

Multiple TTL inputs can be monitored simultaneously using a larger mask.

Example:

TTL T=15

Monitors:

• TTL0
• TTL1
• TTL2
• TTL3

---

Hardware Requirement

To use this method, no soldering modification is required.

However, the SV9 header on the TGGALVO card must be populated with jumpers.

Jumper Configuration

Location:

SV9 header (2x8 header in center-rear of TGGALVO card)

Requirement:

• Install 8 jumpers
• Orientation: front-to-back
• Match orientation of the two adjacent headers.

This connects the backplane signals internally to the card.

---

Known Limitation

Backplane triggers interpreted through TTL_AUXILIARY generate a global TTL input event.

Implication:

• All axes associated with the card will respond to the trigger.
• Individual axes cannot be triggered independently.

To control axes independently:

• The Single Axis command configuration must be updated between scans.

---

Compatibility Question Raised

Concern was raised about whether performing the standard TTL input hardware modification might disrupt the existing workflow.

Current system behavior:

• PLC triggers are already sent across the backplane
• Jumpers are used to route those signals
• These signals successfully trigger Single Axis waveforms.

The question is whether adding the direct TTL input modification would interfere with that backplane-based triggering mechanism.

This remains an open implementation consideration.

[bls337]

I think you only want to do one of these at a time.

I don't know that it would interfere with your existing workflow, but you only need the TTL input hardware modification if you want to use the repeated relative moves.

If you are relying on the single axis waveform you shouldn't need the TTL triggered repeated relative moves. You have to choose between TTL X=2 or TTL X=30.

The TTL_AUXILLARY firmware module also uses polling and can have 250 microseconds of delay. Chris can explain the details if needed.

[jondaniels]

I will chime in and say that I think it is an accident that your firmware has TTL_AUXILLIARY. If it is useful then by all means take advantage. Benefit is you can use the existing card jumpers, no soldering necessary. Downside is the jitter of up to 250us. I

The question is whether adding the direct TTL input modification would interfere with that backplane-based triggering mechanism.

I don't think there would be any interference. An existing signal on the backplane would trigger the galvo card. Optionally the galvo card can output a trigger (on a currently-unused backplane line) to mimic the motorized stage's in/out trigger behavior and leave the PLC logic unchanged.