Troubleshooting & FAQ

Make sure you have completed License Activation for your device type before attempting a connection. EasyGraph requires a valid license key before any device can connect.

If the key is entered and the device is still not found:

• Verify the USB cable is fully seated and the device is powered on.
• For log.flow: confirm the FTDI D2XX driver is installed — see Hardware requirements.
• For IO.flow®: the USB IO-Link master must be connected; the IO.flow converter cable alone is not sufficient.
• Try a different USB port, preferably USB 3.0 for maximum current capacity.

1. Check that the channel is configured for the correct input mode (single / dual channel).
2. Verify the sensor is supplied with 24 V. See Power supply configuration if you are using log.flow.
3. Confirm the signal is HTL level (0..24 V). Standard log.flow variants do not support TTL (0..5 V) signals.
4. If all else fails, disconnect and reconnect the device.

A gray entry means the USB connection was lost (e.g. the cable was unplugged or the device was powered off). Right-click the gray entry and choose Remove. Reconnect the device and use Auto-Connect again.

Online licenses have an activation limit. To move your license, open the License menu on the old PC first and remove the existing software key — this frees the activation slot so you can register it on the new machine.

If the old PC is no longer available, contact VSE to reset your activation.

• Open Windows Device Manager (devmgmt.msc) Ports (COM & LPT) and verify the adapter appears when plugged in. Use that COM number in EasyGraph.
• Ensure no other application (terminal emulator, COM port monitor) is holding the port open.
• Some evaluation units have a cooldown delay before streaming begins. The device settings panel shows the expected wait time — this is normal behavior.

Recordings are kept in volatile RAM until explicitly saved. EasyGraph does not autosave. Always export before closing: right-click the entry in the recordings panel and choose Save as… Protobuf-File [.bin].

Only channels that are visible and enabled in the live graph are recorded. Channels that were hidden or disabled will not appear in the file. Re-enable them before starting the next recording.

• Confirm the threshold value is within the expected signal range. Enable Show Trigger Cursor in the trigger menu to visualize the threshold against live data and adjust by dragging.
• Verify the correct channel and comparator operator are selected.
• Ensure the trigger is armed using the Enable Trigger checkbox or the Trigger button in the live graph panel.

This typically happens in Repeating mode when the signal toggles rapidly. Switch to Hold mode and set a hold duration long enough to bridge the gaps between pulses. See Trigger hold mode for recommended starting values.

• Verify that no other application is holding the COM port.
• Confirm the baud rate, data bits, parity, and stop bits match the sending device (default: 115200/8/None/1).
• Verify that thSimpleSerial data arrives but channel values look wrong"
• Check the unit conversion factor and summand in the channel math settings.
• Verify the decimal separator setting matches the sender (period . vs comma ,).
• If a header row is used for channel naming, ensure the first line is exactly the header with no leading whitespace.

Math channels always receive the raw device value — the signal before any Math Settings conversion. If your source channel is configured to show l/min but the math channel still sees Hz, apply the same gain and offset conversion explicitly inside the math formula.

When a source device is disconnected, the math channel enters an error state and pauses. Reconnecting the device re-enables the math channel automatically.

In Automatic mode the sample rate is inversely derived from the plot history slider — a longer history means lower sample rate. Move the history slider or switch to Manual mode with a fixed rate if you need stable acquisition independent of the view.

If you previously used Set default window startup location and then changed your monitor configuration, the window may be positioned off-screen. Close EasyGraph via the taskbar or Task Manager, then hold Shift during the next launch. This resets the window position to the default centered position for that start.

Disable Auto-Scale in the live graph controls and set the Y-axis range manually using the scroll wheel and drag. The Lock-Min feature fixes the lower Y boundary while letting the upper boundary scale — useful for flow signals that always stay above zero.

Cropping is currently a destructive in-memory operation with no undo. If you saved the original file to disk before cropping you can discard the modified in-memory version and reload it. If the file was never saved to disk before cropping, the original data cannot be recovered. Always save (Save as…) before cropping if you may need the full original later.

Standard log.flow variants (4881, 4881/V, 4881/I) support only HTL signals (0..24 V). The input high threshold is 21 V — a 5 V TTL high level is well below the input high level and will not work. Use a external level shifter before feeding the signal into the log.flow.

See [Digital Inpge input on log.flow_V (pin 4) has an absolute maximum of 10 V. Applying a HTL pulse signal or any voltage above 10 V can permanently damage the analog input stage. Always verify the pinout and signal level of the connected sensor before applying power.

log.flow_I continuously monitors the analog current input for short-circuit conditions. If a persistent fault is detected, the current path is disabled by an internal digital switch and EasyGraph shows a warning message. Remove the wiring fault, then use Re-Enable.. in the device settings to restore the input.

Current sensors must be connected in series, not in parallel. Internally the log.flow_I measures current as a voltage drop across a shunt from pin 4 to GND. Connecting it in parallel with an existing current loop results in incorrect readings and may affect the loop itself. Use a T-adapter or install log.flow_I in series with the sensor.

• Confirm the license key was entered exactly as provided (no extra spaces or missing characters).
• Check whether a firewall or corporate proxy is blocking outbound HTTPS connections from EasyGraph.
• If the key was already activated on another PC and not removed, the activation limit may be reached — see the question about moving to a new PC above.

Contact VSE Volumentechnik GmbH with your proof of purchase. License keys can be retrieved or reissued by VSE support.

• Verify device connection and power state.
• Verify the license key is entered correctly for this device type.
• For serial devices: verify COM port is free and baud/parity settings match.
• Verify no other process holds the port or USB interface.

• Verify channel math settings (factor and summand / unit conversion).