HP TwinTec manual Data Logging Chart Display

DATA LOGGING CHART DISPLAY

You can also display data logged by the TCFI unit on a chart recorder type screen. Data logged by the TCFI unit must be downloaded before it can be displayed, by using the Download Data From TCFI command on the Communications menu. Once data has been downloaded, it is automatically displayed.

The last data logged will appear at the right end of the chart. You can save the data by using the Save File command from the File menu. You can display a previously saved data file by first using the Open File command on the File menu and then using the View Chart command on the View menu.

Note that TCFI data files use a .log extension. You should create a separate folder to store these files.

You have a range of capabilities for analyzing downloaded data displayed in the chart recorder format. You can select two parameters for display. Trace 1 is displayed in red with its Y axis legends on the left side of the chart. Trace 2 is displayed in green with its Y axis legends on the right side of the chart.

The X axis is always elapsed time. You can select from one of three time scales. You can use the scroll bar to move the chart display window in terms of elapsed time. If you hold the left mouse button down within the chart area, a cursor line appears. The exact values of the parameters displayed on trace 1 and trace 2 and the elapsed time appear in windows above the chart. If you want to analyze the elapsed time between two events (for example the time required to accelerate from 0 to 60 MPH), you can move the cursor to the first event and then click on the Reset Time Display button. You can print the displayed chart to any Windows printer by clicking on the Print button (a color inkjet printer is recommended for best results).

Data parameters include: RPM – engine crankshaft RPM

VSS – vehicle speed in MPH

MAP – manifold pressure in In-Hg (29.92 In-Hg corresponds to atmospheric pressure)

TPS – throttle position (0 to 100%)

AFR – air/fuel ratio based on the exhaust gas oxygen sensor reading (10:1 to 20:1). Front and

rear cylinder AFR values can be displayed for data logged by TCFI IID units.

BLM – block learn multiplier (main fuel table correction factor based on exhaust gas oxygen sensor feedback, shown as percent value from 75-125%). Front and rear cylinder BLM values can be displayed for data logged by TCFI IID units.

IAC – idle air control stepper motor position (higher number means more idle air)

IAT – intake air temperature (deg C)

ET – engine cylinder head temperature (deg C)

FRONT INJ, REAR INJ – injector pulse width in milliseconds

FRONT ADV, REAR ADV – ignition advance in degrees BTDC

BAT – battery voltage

USER – user output displayed as digital (on/off) signal. On means that the output is grounded.

Additional data is displayed at the lower right side of the screen. This data includes:

Baro – barometric pressure in In-Hg.

Diagnostic Code – normally blank unless a diagnostic code is set. Refer to the TCFI installation instructions for details.

Engine Status – based on engine temperature and open/closed loop AFR

Log Interval – the actual data logging interval in seconds

The TCFI data buffer stores the last 1600 data points. With a nominal data logging interval of 0.50 seconds, this corresponds to 13.3 minutes of data. You can set higher or lower data logging intervals by means of the PC Link TCFI software Module Parameters screen. Data logging intervals of 0.5-1.0 seconds are suitable for on-road tests; a shorter interval of 0.10 seconds is recommended for dyno tuning.

You can clear the data within the TCFI by using the Clear TCFI Data Buffer command from the Communications menu. If you change the data logging interval, you should also clear the TCFI data buffer.