Intermittent USB Connectivity

Overview

For setups that include Coherent OBIS lasers and an ASI Tiger Controller, some users have reported intermittent serial/USB connection issues. These issues were first observed at CU Boulder and appeared to involve COM port conflicts.

Reported Issues

  1. Intermittent ASI stage connection failure

    • Error example: Unable to connect to the serial port: Access to the port 'COM13' is denied.

    • This was observed in both ASI/Tiger software and navigate.

  2. Errors in navigate logs

    • Example log entry: model - ERROR - asi: ASI stage connection failed.

  3. Unstable stage behavior during imaging

    • In some runs, the stage connected but then moved sporadically during acquisition.

Suspected Cause

The issue appeared to be port competition between the Coherent OBIS laser and the ASI Tiger controller.

  • ASI Tiger controller: COM13

  • Coherent OBIS 561 nm laser (initial): COM14

Despite this assignment, the laser intermittently attempted to use COM13, displacing Tiger access and causing conflicts.

Solution and Verification

  1. Reassigned the Coherent OBIS laser from COM14 to COM9.

  2. Rebooted both the computer and hardware so the new port assignments were applied.

Results

After reassigning the OBIS laser to COM9, the ASI stage remained stable on COM13 with no recurring connection interruptions or uncontrolled stage movement.