Failed to read scanner frequency

Issue: After initiating an acquisition with a Resonant imaging system configured, the following error message showed on the command window before canceling the acquisition.

Failed to read scanner frequency. Period clock pulses not detected.
Verify zoom control/period clock wiring and MDF settings.

Background: ScanImage® sends a 0-5V analog voltage to the resonant scanner driver board corresponding to the amplitude of the scan mirror deflection. During an acquisition with 1x Zoom, the signal will be held at 5V until the zoom is changed or the acquisition ends.

In order to know the phase of the mirror (so we know where to assign pixel locations), the resonant driver also features a sync port which outputs a TTL pulse once per cycle of the scan mirror deflection. The probable causes for failing to read the scanner frequency are given in the error message - either the mirror isn’t actually resonating, or it is resonating but the sync signal isn’t being read. Ensure the sync signal is connected to the port which was specified in the machine configuration editor.

Troubleshooting: Identify whether the issue is with Command signal or the Feedback signal

You can tell if the resonant mirror is not resonating if you cannot hear the 8kHz hum of the resonant mirror even when 5V is applied to the zoom command. Depending on if you’re using a vDAQ or NI DAQ hardware, you can use the vDAQ Test panel (command: scanimage.guis.VdaqTestPanel) or NI Max to send 5V to the command input of the resonant driver. Otherwise, you can use a function generator to send 5V.

If you can hear the resonant driver, check to see that the Sync is working by verifying that the driver is sending a pulsed TTL signal (at approximately the frequency of your scanner) to the appropriate input of the DAQ (or oscilloscope input).

If both work correctly, then it is probable that the MDF has the wrong ports allocated

Solution

Identify the root cause of the problem

Here are some probable causes for each issue in the order that you should check them.

  • Cannot hear the 8kHz hum

    • Mirror is just quiet (see if there is laser deflection)

    • Resonant Driver is not powered on

    • Command Signal is not connected

      • Incorrect MDF zoom command port allocation

      • Missing cable

      • faulty cable

        • signal + wire is conducts between daq output signal + and controller input signal +

        • signal - wire is between daq output signal - and controller input signal -

    • Resonant Scanner is defective

  • No pulses at the sync

    • Resonant Driver is not powered on

    • Sync Signal is not connected

      • Incorrect MDF sync por allocation

      • Missing cable

      • faulty cable

        • signal + wire is conducts between daq output signal + and controller input signal +

        • signal - wire is between daq output signal - and controller input signal -

    • Resonant Scanner is defective