The user interface

The user interface to the TDS-1 consists of one button. When pressed quickly, the button functions as a "next" button, advancing to the next display mode, or changing values in a configuration mode. Holding the button down for 2 seconds or more enters configuration mode from normal mode, advances to the next configuration screen, or exits configuration mode.

You move from one mode to another by either using a short button press, or a long button press. How long is a long button press? The TDS-1 will tell you when you have held the button long enough by displaying this 'BU'tton screen:

If you unintentionally hold the button too long and see the 'BU' screen, simply release the button, and hold it down for more than two seconds again.

Modes

There are two categories of modes: operational modes and configuration modes. The operational modes display values, such as boost, volts, etc. The configuration modes are used to change the way values are displayed.

Configuration Modes

There are three different configuration modes: MAP range, IAT units, and MAP units.

The MAP range parameter determines how the TDS-1 converts the MAP signal from the ECU from a voltage into pressure. This depends on what kind of MAP transducer you have in your ECU. The Ur-S4/S6 came from the factory with a 2.5 bar sensor. If you have "chipped" your car, you may have a 3.0 bar sensor. If you have a VMAP, then you may be using it as a 2.8 or 2.9 bar sensor. Naturally, if you do not configure the MAP range on the TDS-1 correctly, then the reported pressure values will be incorrect.

The IAT units parameter simply determines whether the Intake Air Temperature sensor value is displayed in degrees Fahrenheit or Celsius.

The MAP units parameter determines how the manifold pressure is displayed.

Operational Modes

There are seven operational modes: Atmospheric pressure, Voltmeter, Instant IAT, Peak-hold IAT, Peak-hold manifold pressure, Instant manifold pressure and Radio pass-through.

Atmospheric pressure mode displays the active atmospheric pressure value. This value can be by turning the ignition to ON, from OFF, not cranking the engine, and waiting approximately 5 seconds. The TDS-1 will read the pressure of the Manifold Absolute Pressure (MAP) sensor in the ECU and use that as a reference point for relative measurements.

The voltmeter mode displays the voltage present at the TDS-1. Assuming the TDS-1 is properly installed, this should be identical to the voltage at the battery.

There are two Intake Air Temperature (IAT) modes. The Instant IAT mode averages the IAT reading over a period of approximately 330 milliseconds (1/3 second) and displays it directly. The peak hold IAT mode averages IAT readings for only 20 milliseconds (1/50 second) and displays the highest reading read over the last 5 seconds. The peak value will tend to be slightly higher, even when the IAT is not changing. This is due to small amounts of noise on the IAT signal.

There are two manifold pressure modes. One is a peak hold mode which holds the highest reading over the last 5 seconds, and the other is an instantaneous mode. Both modes average the MAP signal over a 20 millisecond period to obtain their readings. Optionally the manifold pressure modes can be configured to display the radio display signal instead of vacuum readings.

The radio pass-through mode is used to display the output of a Gamma CC radio in the instrument cluster, as if the TDS-1 were not installed.

Manifold pressure display units

In the manifold pressure modes, there are three options for display. The normal mode displays pressure in units of PSIG (Pounds per Square Inch Gauge) for boost and inHg (inches of mercury) for vacuum. There is an absolute pressure mode, which uses units of millibars. And finally there is the PSIG only mode, which displays boost in PSIG, but instead of displaying vacuum readings, it relays the radio display signal.

Navigating through the modes

This diagram shows the "location" of each of the modes. The arrows show the result of a button press in each mode.

More examples of display modes

Voltmeter mode, engine off
Voltmeter mode, engine running
Atmospheric pressure If 'A' is flashing, then this value was measured during this power cycle. If the 'A' is solid, then this value is the stored value from the last time the atmospheric measurement procedure was successful. In either case, this is the value used to convert from absolute pressure to PSIG.   See Atmospheric Pressure Measurement Mode below for more information.
Instantaneous boost mode 4.6 PSIG (PSI above measured atmospheric)   The 'B' (for 'B'oost) in the center line indicates that this value is greater than the recorded atmospheric pressure.   In PSI/inHg mode, the 'B' also indicates the units for the numeric value. When 'B' is indicated, the units are in PSI. When the 'B' is not present, the units are inches of mercury.
Peak boost mode Zero PSIG (at atmospheric, i.e. engine off)   The 'UM' in the bottom line indicates that this mode uses 'U'r-units (i.e. PSI/inHg) and in 'M'aximum (peak) hold mode.   The 'M' flashes when the displayed value (the peak) is above the current value. This indicates that the peak is being held.   The 'B' (for 'B'oost) in the center line indicates that this value is greater than the recorded atmospheric pressure.
Peak boost mode 1020/1021 millibars absolute (1/4 sec exposure)   The 'MM' in the bottom line indicates that this mode displays 'M'illibars, in 'M'aximum (peak) hold mode.   The second 'M' flashes when the displayed value (the peak) is above the current value. This indicates that the peak is being held.   The 'B' (for 'B'oost) in the center line indicates that this value is greater than the recorded atmospheric pressure.
Peak boost mode 14.3 inches of mercury (inHg) of vaccuum   Note that peak values are not held when the pressure is below atmospheric, and the vacuum display behaves the same as the instantaneous pressure mode.   The lack of a 'B' character in the middle line indicates that this value is below the recorded atmospheric pressure. In the PSI/inHg mode, the value is in inHg below atmospheric (29.x would be a total vaccuum).
Configuration mode entered   Holding the button down for 2 seconds enters configuration mode, or advances to the next screen if already in configuration mode,   When the button is held down for 2 seconds, this 'B' 'U' (tton) screen is displayed until the button is released. This provides feedback that the button has been held down long enough.
Configuration mode - boost mode (units)   When in one of the boost modes (peak or instant), holding down the button enters the boost configuration mode.   The first boost configuration screen allows you to toggle between 'M'etric mode and 'U'r-units mode. The displayed value is the highest possible pressure reading for the currently selected pressure transducer (see below). Pressing the button quickly (i.e. less than 2 seconds down) toggles between the two modes.   Hold the button down for more than 2 seconds to advance to the next boost configuration mode.
Configuration mode - boost mode (MAP type)   The TDS-1 can be used with pressure transducers with different maximum pressures. When you hold the button from the first boost configuration screen, you enter the second boost configuration screen which allows you to set the MAP pressure to voltage function.   The image at right shows the selection for a 3.0 bar MAP sensor.   Press the button quickly to advance to the next MAP value.
Configuration mode - boost mode (MAP type)   If you have a VMAP in your race car, you may need this 4.0 bar setting.
Configuration mode - boost mode (MAP type)   The 2.5 bar setting is required for cars which still use the stock Ur-S pressure transducer.
Configuration mode - boost mode (MAP type)   If you have a 20v turbo 200, you might have the 2.0 bar sensor.   Once the desired maximum MAP value is selected, hold down the button for 2 seconds and you will return to the normal operating mode.   The MAP value selected will be stored in the TDS-1 EEPROM and you will not need to change this value unless you change your ECU.
Intake Air Temperature, Instantaneous mode   The default units are degrees Celsius.   Instantaneous IAT mode always displays one 'M' centered in the bottom line. The units (F or C) are indicated in the center line.
Intake Air Temperature, Instantaneous mode   The units can be changed to Fahrenheit in the configuration screen. Hold the button for two seconds while in IAT mode to enter the Celsius/Fahrenheit configuration screen.   Instantaneous IAT mode always displays one 'M' centered in the bottom line. The units (F or C) are indicated in the center line.
Intake Air Temperature, Peak hold mode   The peak hold mode for IAT holds the highest temperature measured in the last 5 seconds.   Peak IAT mode always displays two 'MM' characters centered in the bottom line. The units (F or C) are indicated in the center line.

Atmospheric Pressure Measurement Mode

The TDS-1 offers a PSIG mode, which displays the boost or vaccuum value relative to atmospheric. Because the ECU has an absolute pressure transducer, the atmospheric pressure must be measured to use the PSIG mode accurately. Additionally, even in the absolute pressure mode (millibars), a 'B' symbol will be present when the measured pressure is above atmospheric.

The TDS-1 can only measure atmospheric pressure when the engine is not running, but the car is otherwise "on". To do this, turn the key to the ON position from OFF and wait for approximately 5 seconds. The TDS-1 monitors the battery voltage when it first receives power, and if the voltage stays within 11.5-12.5 volts for 5 seconds, it determines that the engine is not running and is not being cranked (which also affects the pressure measurement). After the 5 seconds are up, the TDS-1 will display the measured atmospheric pressure reading on the display with a flashing 'A' symbol.

Atmospheric pressure measured   1021 millibars is 30.23 inches of mercury