This section aims to help the user solve and avoid problems while using the software and operating the instrument.

Common Problems

Your HF2 Series Instrument is an advanced piece of laboratory equipment which has many more features and capabilities than a traditional lock-in amplifier. In order to benefit from these, the user needs access to a large number of settings in the LabOne User Interface. The complexity of the settings might overwhelm a first-time user, and even expert users can get surprised by certain combinations of settings. To avoid problems, it’s good to use the possibility to save and load settings in the Config Tab. This allows one to keep an overview by operating the instrument based on known configurations. This section provides an easy-to-follow checklist to solve the most common mishaps.

Table 1. Common Problems
Problem Check item

The software cannot be installed or uninstalled

Please verify you have administrator/root rights.

The software cannot be updated

Please use the Modify option in Windows Apps & Features functionality. In the software installer select Repair, then uninstall the old software version, and install the new version.

The Instrument does not turn on

Please verify the power supply connection and inspect the fuse. The fuse holder is integrated in the power connector on the back panel of the instrument.

The HF2 Instrument turns on but delivers obviously wrong measurements

Please verify the power system setting on the back panel of the device is set to the power system of your country (110 V / 60 Hz, 220 V / 50 Hz). Make sure the fuse holder is set to the correct power supply position. This means that the wanted power supply label, 230 V or 115 V, must be positioned beside the edge of the power socket (e.g. not beside the power switch).

The HF2 Instrument performs poorly in a country with 100 V supply system (e.g. Japan)

if no 100 V to 110 V transformer is used, the internal power supplies might be below specifications and some circuits might perform worse than specification. Users in countries with 100 V supply system are warmly recommended to use an external transformer (delivered with the instrument).

The HF2 Instrument shows limited data throughput on USB

although the host computer requirements are not particularly demanding, highest performance in USB throughput will require a performing desktop. The USB might be limiting the data throughput, please see Maximum sample readout rate for more details. Many concurrent transfers on the USB will limit the individual transfer. In particular the Scope should be turned off when not needed by the application. The status of the USB transfer can be monitored in the STATUS_TAB.

The Instrument performs poorly in single-ended operation

the signal inputs of the instrument might be set to differential operation. Please ensure that differential input mode is turned off in the Lock-in Tab or In / Out Tab.

The HF2 Instrument has a high input noise floor

the USB cable connects the Instrument ground to computer ground, which might inject some unwanted noise to the measurements results. In order to decouple the computer from the Instrument consider using an electrically isolating USB range extender supporting 480 Mbit/s data transfer rate. Zurich Instruments recommends the models USB 2.0 Ranger 2201 (Icron technologies) and U-Link USB 2.0 extender (Sewell). The power supply delivered with the range extender may need to be exchanged with a more stable power supply for optimum noise performance.

The Instrument performs poorly at low frequencies (below 10 kHz) :

the signal inputs of the instrument might be set to AC operation. Please verify to turn off the AC switch in the Lock-in Tab or In / Out Tab.

The Instrument performs poorly during operation

the demodulator filters might be set too wide (too much noise) or too narrow (slow response) for your application. Please verify if the demodulator filter settings match your frequency versus noise plan.

The Instrument performs poorly during operation

clipping of the input signal may be occurring. This is detectable by monitoring the red LEDs on the front panel of the instrument or the Input Overflow (OVI) flags on the STATUS_TAB of the user interface. It can be avoided by adding enough margin on the input range setting (for instance 50% to 70% of the maximum signal peak).

The Instrument performs strangely when working with the HF2-MF Multi-frequency Option

it is easily possible to turn on more signal generators than intended. Check the generated Signal Output with the integrated oscilloscope and check the number of simultaneously activated oscillator voltages.

The Instrument performs close to specification, but higher performance is expected

After 2 years since the last calibration, a few analog parameters are subject to drift. This may cause inaccurate measurements. Zurich Instruments recommends re-calibration of the Instrument every 2 years.

The Instrument measurements are unpredictable

Please check the Status Tab to see if there is any active warning (red flag), or if one has occurred in the past (yellow flag).

The Instrument does not generate any output signal

verify that signal output switch has been activated in the Lock-in Tab or in the In / Out Tab.

The Instrument locks poorly using the digital I/O as reference

make sure that the digital input signal has a high slew rate and clean level crossings.

The Instrument locks poorly using the auxiliary analog inputs as reference

the input signal amplitude might be too small. Use proper gain setting of the input channel.

The sample stream from the Instrument to the host computer is not continuous

Check the communication (COM) flags in the status bar. The three flags indicate occasional sample loss, packet loss, or stall. Sample loss occurs when a sampling rate is set too high (the instrument sends more samples than the interface and the host computer can absorb). The packet loss indicates an important failure of the communications to the host computer and compromises the behavior of the instrument. Both problems are prevented by reducing the sample rate settings. The stall flag indicates that a setting was actively changed by the system to prevent UI crash.

The Instrument is connected but there is no communication to the computer

check the clock fail (CF) flag in the status bar. This abnormal situation can occur if "Clk 10 MHz" is selected as Clock Source but no clock signal is fed to the Instrument. If Internal clock source is selected and the flag is still active, then the situation might indicate a serious hardware failure. In this case contact Zurich Instruments support team at

The LabOne User Interface does not start

Verify that the LabOne Data Server (ziServer.exe) and the LabOne Web Server (ziWebServer.exe) are running via the Windows Task Manager. The Data Server should be started automatically by ziService.exe and the Web Server should be started upon clicking "Zurich Instruments LabOne" in the Windows Start Menu.

If both are running, but clicking the Start Menu does not open a new User Interface session in a new tab of your default browser then try to create a new session manually by entering in the address bar of your browser.

The user interface does not start or starts but remains idle

Verify that the ziServer HF2 Instrument has been started and are running on your host computer.

The user interface is slow and the web browser process consumes a lot of CPU power

Make sure that the hardware acceleration is enabled for the web browser that is used for LabOne. For the Windows operating system, the hardware acceleration can be enabled in Control Panel → Display → Screen Resolution. Go to Advanced Settings and then Trouble Shoot. In case you use a NVIDIA graphics card, you have to use the NVIDIA control panel. Go to Manage 3D Settings, then Program Settings and select the program that you want to customize.

Location of the Log Files

The most recent log files of the LabOne Web and Data Server programs are most easily accessed by clicking on btn uielements logs um in the LabOne Device Connection dialog of the user interface. The Device Connection dialog opens on software start-up or upon clicking on btn uielements sessiondialog um in the Config tab of the user interface.

The location of the Web and Data Server log files on disk are given in the sections below.


The Web and Data Server log files on Windows can be found in the following directories.

  • HF2 Data Server (ziServer.exe) started by the service (ziService.exe):

    C:\Windows\ServiceProfiles\LocalService\AppData\Local\Temp\Zurich Instruments\LabOne\ziServerLog
  • HF2 Data Server started manually:

    C:\Users\[USER]\AppData\Local\Temp\Zurich Instruments\LabOne\ziServerLog
  • LabOne Web Server (ziWebServer.exe):

    C:\Users\[USER]\AppData\Local\Temp\Zurich Instruments\LabOne\ziWebServerLog

The C:\Users\[USER]\AppData folder is hidden by default under Windows. A quick way of accessing it is to enter %AppData%\.. in the address bar of the Windows File Explorer.

windows explorer app data
Figure 1. Using the %AppData%\.. shortcut in Windows Explorer to access the hidden folder.

Linux and macOS

The Web and Data Server log files on Linux or macOS can be found in the following directories.

  • HF2 Data Server (ziServer) started manually:

  • HF2 Data Server if started automatically (Linux only, by the Zurich Instruments udev rule):

  • LabOne Web Server (ziWebServer):


Prevent web browsers from sleep mode

It often occurs that an experiment requires a long-time signal acquisition; therefore, the setup including the measurement instrument and LabOne software are left unattended. By default, many web browsers go to a sleep mode after a certain idle time which results in the loss of acquired data when using the web-based user interface of LabOne for measurement. Although it is recommended to take advantage of LabOne APIs in these situations to automate the measurement process and avoid using web browsers for data recording, it is still possible to adjust the browser settings to prevent it from entering the sleep mode. Below, you will find how to modify the settings of your preferred browser to ensure a long-run data acquisition can be implemented properly.


  1. Open Settings by typing edge://settings in the address bar

  2. Select System from the icon bar.

  3. Find the Never put these sites to sleep section of the Optimized Performance tab.

  4. Add the IP address and the port of LabOne Webserver, e.g., or to the list.


  1. While LabOne is running, open a tab in Chrome and type chrome://discards in the address bar.

  2. In the shown table listing all the open tabs, find LabOne and disable its Auto Discardable feature.

  3. This option avoids discarding and refreshing the LabOne tab as long as it is open. To disable this feature permanently, you can use an extension from the Chrome Webstore.


  1. Open Advanced Preferences by typing about:config in the address bar.

  2. Look for browser.tabs.unloadOnLowMemory in the search bar.

  3. Change it to false if it is true.


  1. Open Settings by typing opera://settings in the address bar.

  2. Locate the User Interface section in the Advanced view.

  3. Disable the Snooze inactive tabs to save memory option and restart Opera.


  1. Open Debug menu.

  2. Go to Miscellaneous Flags.

  3. Disable Hidden Page Timer Throttling.