Data Logging Settings
Capoworks ECU and TunerStudio provide two complementary logs. TunerStudio records live channels over the laptop connection; supported ECUs can also log onboard to an SD card for later analysis.
Basic TunerStudio logging settings
The TS logging settings can be found in the Data Logging tab up the top.
Start & Stop Logging
Logging can be started and stopped with CTRL+L & CTRL+K respectively.
Logging Profiles
Custom logging profiles can be configured to add or take away specific parameters. Typically the default profile is acceptable as it logs all parameters.
Triggered Logging
Triggered logging is useful in that it allows the user to set the conditions of when a log should begin. The manual setting has the logs started and stopped by the user. The simple settings allow for logging to be started and stopped when a parameter is above, below or equal to a user-specified value e.g. start logging when CLT is above 75. Expressions are more complex but allow for a series of conditions to be used e.g. [RPM] > 6000 && [TPS] > 90 will activate when the TPS is over 90% and the RPM is over 6000.
Data Logging Preferences
The preferences allow for the data log formatting and naming to be modified. Typically these can be left as the default settings of MLG format and naming on log start with the tune saved to the log.
Other Settings
By pressing ALT+V, the log can be opened in MegaLogViewer for analysis.
By pressing ALT+L, the selected data log folder will be shown.
SD card logging
At startup, the logger waits briefly for the USB stack. If a card and USB host are present, the card is handed to USB mass storage and internal logging does not run. Otherwise the firmware attempts to mount the card and log internally. A missing card or mount failure produces no internal log.
Data Rate
In TunerStudio, the polling rate can be set under Communications > Data Rate. This controls how often the PC requests live data; it does not increase the firmware's calculation rate. Use a rate that the connection and selected channel set can sustain, and confirm the log contains regular samples before relying on a transient capture.
SD logging settings
The SD logging settings are found under Controller > SD Card Logger. Although the INI exposes a rate up to 250 Hz, the firmware clamps the normal logger to 1-100 Hz. Each record snapshots the output-channel space and writes the defined log fields from that snapshot. Higher rates increase card traffic and file size; the logger prints its field count, bytes per record, effective rate, and calculated bytes per second at startup.
The file is synchronised every two seconds. An abrupt power loss can therefore leave the card's directory length behind the data that was written since the last sync. A write error or full card stops the logger and raises a warning; it does not retry continuously.
For the SD logger mode, Normal writes an MLG file from the configured
output channels. Trigger writes a .teeth composite trigger log and does
not use the normal SD rate. Trigger mode generates much more event data and
uses the shared composite-logger buffer.
Diagnostic and High speed logger
Trigger Logger records primary and cam edge state for each logged tooth event. It only records while the engine sniffer is enabled, which in turn is gated by Engine Sniffer Threshold RPM. A 250-entry buffer is published when full, or on the next logged event after five seconds. If no buffer is ready, TunerStudio receives an out-of-range response, not an empty sample set.
Trigger Oscilloscope is different: it samples dedicated analog trigger
inputs at 8-bit resolution and is available only in builds compiled with
TRIGGER_SCOPE. Channel names and input pins are board-specific. Use the INI
and pinout for the exact board target rather than assuming universal channels.
At higher RPM the firmware deliberately stops adding events to the sniffer path. Adjust Engine Sniffer Threshold to cover the event being investigated; a missing trace above that limit is not proof that the trigger stopped.