Philips Brilliance 64: A-plane collimator error blocks startup
What happened
The scanner would not start, reporting an A-plane collimator fault, and at gantry start the operators noticed a delay before the software window appeared.
What was checked
- Polled the collimator control loop over CAN to see whether the A-plane node answered correctly.
- Checked the e-stop loop, which had also thrown complaints in this case.
Cause
The engineers found that the DMC parameters for the A-plane collimator had been lost, so the drive no longer matched the configuration the system expected and the startup check blocked the launch.
What was done
The DMC parameters for the A-plane collimator were restored from the calibration file — a procedure from the manufacturer's service documentation, done by authorised personnel — followed by a system restart. The collimator error cleared and the scanner started normally. The delayed appearance of the startup window remained and was, in this case, probably related to the age of the host station and the long CAN polling; the reported e-stop loop message was not finally closed out in this case.
Safety
Since the collimator defines the X-ray beam width, after any collimator parameter work verify blade motion and the e-stop chain, and perform a beam-width/collimation check per the manufacturer's documentation before returning the scanner to clinical use.
Lesson: When a subsystem fault blocks startup, check the integrity of the drive's stored parameters before suspecting hardware, and log any residual symptoms separately instead of assuming the parameter restore fixed them.
Covered in the course: CT Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.