Hi everyone,
We are also experiencing persistent issues receiving triggers from our Philips MR7700 scanner using the Lumina Standard Controller (3G). The problem occurs in both keyboard and Serial Lumina modes.
Using both Python and MATLAB, we intermittently miss triggers without any identifiable pattern. This includes, on occasion, the first trigger in the sequence, which is especially critical for synchronizing our task with the scanner sequence. Additionally, when the first trigger is received, we typically only get either 'pressed': True or 'pressed': False, without reliable alternation.
Below are two example logs from an experiment with a TR of 3.3 seconds:
Example 1: First trigger sends 'pressed': True, then we miss 5 triggers in one instance and 6 in another
| 72.5079 | DATA | Waiting for MRI trigger… |
|---|---|---|
| 455.0221 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 454768} |
| 455.0224 | DATA | MRI trigger received |
| ----- 5 Triggers missing here -------- | ||
| 16.7492 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 471509} |
| 16.7658 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 471516} |
| 33.4996 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 488259} |
| 33.5166 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 488265} |
| 36.8525 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 491609} |
| 36.8692 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 491615} |
| 40.2061 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 494959} |
| 40.2229 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 494960} |
| ----- 6 Triggers missing here ----- | ||
| 60.3091 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 515059} |
| 60.3258 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 515063} |
Example 2: First trigger received correctly, but occasional triggers still missing
| 334.3228 | DATA | Waiting for MRI trigger… |
|---|---|---|
| 1334.8120 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 1334544} |
| 1334.8138 | DATA | MRI trigger received |
| 0.0190 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 1334547} |
| ----- 1 Trigger missing here ----- | ||
| 6.7082 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 1341244} |
| 6.7252 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 1341246} |
| ----- 1 Trigger missing here ----- | ||
| 13.3986 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 1347943} |
| 13.4156 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 1347949} |
| ----- 1 Trigger missing here ----- | ||
| 20.1054 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 1354643} |
| 20.1217 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 1354644} |
| 23.4587 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: False, ‘time’: 1357993} |
| 23.4759 | DATA | mri_trigger={‘port’: 2, ‘key’: 4, ‘pressed’: True, ‘time’: 1357994} |
Troubleshooting steps taken so far:
- Increased TTL pulse duration
We extended the pulse width from the scanner to both 500 microseconds and 5000 microseconds, but this did not improve trigger detection reliability. - Confirmed trigger output from scanner
The LED on the interface box (where the BNC cable connects to the Lumina system) lights up consistently with every scanner pulse, confirming that the scanner is reliably sending the triggers. - Tested multiple software setups
The issue occurs across both Python and MATLAB scripts, and using both ASCII and RID protocols, suggesting the problem is not software-specific. - Updated Lumina firmware
We updated the firmware approximately 5 months ago, but the problem persists. The current firmware version is shown below.
Current firmware version:
Lumina Standard Controller (3G)
(c) Copyright Cedrus Corporation, 2021
0E2M13
Jan 17 2022
15:26:27
Do you have any suggestions for resolving this issue?
Best regards,
Francisco