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M91 firmware update

Teslameter softwareLatest versionRelease dateSizeDownload
Firmware1.6.20210106032021-02-0444 MBfasthall.lsfw
Operating system2.6.42020-09-29272 MB


XIP OS update instructions

Firmware update process

The easiest way to update instrument firmware is online:

  1. Provide the instrument with an Internet connection using Wi-Fi or Ethernet
  2. Access update screen (System settings > Update)
  3. The instrument will detect the latest firmware version, follow on-screen prompts to download and install the update

Updating an offline instrument is accomplished with the following steps:

  1. Click on the desired version number below. This is a link to the .lsfw firmware update file
  2. Copy or save the .lsfw file onto the root directory of a USB flash drive. Make sure it is the only .lsfw file in that location
  3. Plug the flash drive into the USB-C port on the back of the instrument, if you don't have a newer flash drive with a USB-C connection, use the adapter that was supplied with the instrument
  4. Restart the instrument to be given the option to perform a firmware update.
  5. Disconnect the USB flash drive once the update is complete

M91 firmware changelog

Rev 1.6.2021010603 - 2021-02-04


  • GPIB terminators detail moved to info circle
  • GPIB now works at 3 MB for higher throughput
  • Memory conservation processes improved


  • :RESult[:STANdard][:SUMMary]? query inconsistencies and errors
  • Link commands missing and ignoring Sampling Time parameters
  • Sheet Hall Coefficient Standard Error units naming is incorrect
  • GPIB comms timeout issue
  • Broken wire detection with high resistance samples inconsistent
  • GPIB info circle sometimes does nothing when adapter is unplugged
  • Cancel button on GPIB address selection dialog does not cancel the selection
  • DC Hall standard result query order is incorrect
  • DC Hall missing RESult[:STANdard]:POINts? query

Rev 1.4.2020073106 - 2020-08-07


  • Allow user settable sampling time on all measurements
  • Add support for external GPIB connection. Implement SCPI commands for display settings and display lock
  • Remove redundant Contact Check from optimization sequence
  • Add enhanced error messages and diagnostic data to optimization process
  • Modify current autoranging sequence to optimize hardware performance
  • Improve display formatting of numerical values
  • Change default initial excitation current in Contact Check Optimization to 100 mA
  • Improve blanking (settling) time determination
  • Add minimum SNR check to DC Hall measurement
  • Display "High Resistance" on main page when option is enabled
  • Determine if broken wire exists during contact check and notify user
  • Allow for full factory reset of instrument


  • Update broken wire check logic to account for high resistance option license
  • Fix off by one issue when calculating DC hall results with field reversal
  • Allow contact check to be properly canceled when blanking (settling) time is being calculated
  • Clear out previous four-wire measurement results before next test is run
  • Fix incorrectly reported carrier type in DC Hall measurement
  • Improve measurement auto-ranging when using voltage excitation (Hi-Res) mode
  • Update four-wire measurement to accept excitation measurement range

Rev 1.3.20191119x - 2019-11-19


  • Zero and negative field values can be entered for DC Hall and FastHall applications
  • Improved measure autorange setpoints to enhance measurement linearity

Rev 1.3.2019091701 - 2019-09-17


  • Default sample thickness setting now dependent upon if resistivity measurement was run prior in sequence or not
    • DEFault = Set to 0 m if resistivity test not run (added)
    • DEFault = Set to measured resitivity result (no change)


  • Incorrect displayed measurement range (not identical to programmed range in all states)
  • Improved error messaging when user entered sample thickness is invalid value or format

Rev 1.3.2019080101 - 2019-08-01


  • When using optimized setting and in voltage source mode, improved range and compliance auto parameter selection


  • Improved functionality when cycling into and out of sleep mode

Rev 1.2.2019053002 - 2019-05-30

Initial release