2E0 Wideband with Display (Obsolete 2007)

This model was replaced by the 3E range in January 2007.

The 2E0 was available in DIY form (electronics assembly required) as the 2E0 DIY kit.

For a current DIY model with display, check the 2Y DIY range.

The Tech Edge 2E0 integrates a wideband Lambda unit with a 3 digit display. It's suitable for handheld and on-dash as well as other applications where logging is required, but where 2A0's and 2B0's additional on-board logging memory is not required.

2E0 does not include any thermocouple inputs, and has only 2 user channels (but one is differential) and does include RPM logging. 2E0 includes the enhanced pump cell control technology found in newer WBo2 units.

The green 10 pin removable screw terminal connector at the side (see the image at left) provides various inputs and outputs (I/O). The label on the top of the unit describes these I/O pins which are numbered left (1) to right (10).

• Analogue Inputs are U1 and U2. Note that U2 has differential inputs with U2+ the signal input and U2- signal GND which can be above or below real GND level.
• Wideband Output WB+ (also known as WB_lin+) is referenced to the (ground) level on WB-.
• an onboard regulator also supplies 5 Volts on 5V line, for powering external devices such as pressure or temperature sensors.
• GND, or negative power connection.
• RPM inputs for connection to a conventional ignition coil (COIL), or the LO input accepts a low voltage (5 Volt level) pulse input.

In addition to these signals, the RJ45 connector at the rear of the unit (see the image at right) carries the following signals. Note that some of these are duplicates (^*) of signals on the green 10 pin connector :

• RS232 input/output for RS232 logging and PC maintenance (R_x, T_x & GND pins 2, 3 & 5).
• WB_lin(+)^*, the single-ended linear wideband output (pin 4).
• SV_out, the programmable output (for LD01, etc. pin 1)
• NB_sim^*, the programmable narrowband output (pin 6).
• 12 Volts, current limited for a display (pin 8).
• GND^* or negative power connection (pin 5).

Inbuilt LED Display

The domed LED and FUNC buttons, on the label, control the display. clicking the LED button cycles through a four predefined brightness levels so the unit can accommodate daytime use on a dashboard and lower brightness levels for night time or indoor usage. The FUNC button swaps the display between AFR and Lambda display modes.

The status and error messages shown on the display are described below.

Software

The 2E0 unit is software compatible with the other version 2.0 units and calibration, configuration and logging software is available.

2E0 Connection Overview

The image at left shows various parts (highlighted in blue in the text) of 2E0 and how 2E0 is connected to other WBo2 wideband components. Note: some JavaScript pop-up images of parts are available.

Clockwise from the bottom right, the LSU (UEGO support may be offered later) sensor is connected via the sensor cable (comes in various lengths for different applications). The sensor cable's circular 8 pin connector mates with the 2E0 unit. 2E0 needs a source of power provided by the two pin power cable.

On the back of the case are an 8 pin (RJ45) connector for PC RS232 connectivity (config & logging) and for optional connection to an intelligent display. The top of the case has two buttons, with the left LED button controlling the displays brightness and the right FUNC button toggling between AFR and Lambda modes.

The side of the case carries a 10 pin green unpluggable connector with voltage outputs and various logging inputs. Immediately to the left of the green connector is the AMBER heater LED.

The left case end holds the large 3 digit 7 segment display. The red status LED of other WBo2 models is replaced by the right most decimal point of the display.

Each connector and associated inputs & outputs are described in detail below. See also the brief connector summary.

Side of 2E0, Y4.

Back of 2E0, Y1, Y3 & Y2.

WB_lin+ Pin 5/Y4 & WB_lin- Pin 4/Y4 Wideband Output

The most accurate of the 3 voltage outputs is WB_lin which is generated by a 12 bit DAC using a 65 word lookup table (with linear interpolation). A special feature of 2E0's WB_lin is what we have called a differential output which is designed to reduce the amount of noise and possible voltage offset errors seen by a device connected to WBlin. The WBlin differential output is described fully here. WBlin can be re-programmed using the Config utility to cover any part of the AFR range from Lambda = 0.6 to free-air and 0 to 5 Volt output.

Note that pin 4/Y1 (ie. pin 4 of the RJ45) also carries the WB_lin+ signal, but remember that the WB_lin-GND shunt (see details) should be installed if this single ended output is used instead of the differential +/- output.

The default linear wideband output mapping is shown in the image at right.

To convert the default WBlin voltage to an AFR simply multiply the measured voltage by 2 and add 9. This is shown in the graph at left. The advantage of a linear output is that it's easy to write a conversion function from the wideband voltage to AFR.

SV_out Pin 1/Y1 (Pin 1 on RJ45) Compatibility Output

To generate SV_out, the processor uses a 65 word lookup table with linear interpolation. It converts the normalised pump current (Ipx) into a 10 bit value representing SVout. A hardware PWM (Pulse Width Modulation) pin on the processor generates the actual SVout voltage.

SVout is compatible with the Vout signal from the original oz-diy-wb unit (and the 1.5 unit's Vwb). It can be used to drive the analogue LD01 display (or the older 5301 if you change its connector). Note that the 12 bit WBlin can be re-programmed to use the SVout table, so if you're not using WBlin and you want a more accurate SVout voltage, you should consider reprogramming WBlin. Remember however that SVout covers the full range of full-rich (Lambda=0.6) to free-air, the voltage range is small (less than 3 Volts) so measuring resolution is reduced compared to using a smaller AFR range over a larger voltage range.

The default SVout, shown at right, varies between about 1.0 Volt for a very rich mixture (Lambda=0.6 or AFR=9), to 2.50 Volts for a stoic mixture, and to 3.1 Volts for a lean mixture (AFR=25). In free-air the SVout should be exactly 4.00 Volts when the unit has been free-air calibrated correctly.

The default AFR vs. SVout relationship is shown in the Vout table/graph page. The analogue Vout is a continuously available signal that may be logged with a high speed logger. We recommend at least a 10 bit converter for best accuracy.

NB_sim Pin 6/Y4 Simulated Narrowband Output

A synthesised narrowband (NB_sim) voltage is produced by the onboard microcontroller using a 10 bit A/D PWM converter (with single pole filter), and a 65 word lookup table. Linear interpolation improves lookup accuracy. The full 0 to 5 Volt output is available, but restricting the output to 0 to 1 volt reduces the number of possible steps to around 200 (~5 mV per step).

As well as pin 6 of the green connector (Y4), pin 6/Y1 (ie. pin 6 of the RJ45) also carries the NB_sim signal.

The NB output is designed to be compatible with the raw output of a Bosch LSM-11 sensor. Refer to this eXcel spreadsheet for the graph of the default NBsim vs AFR.

As NBsim can re-programmed it is possible to do a number of interesting things such as fooling the engine's ECU (if equipped with a NB sensor) into running richer or leaner than it would do otherwise.

The 2E0's RJ45 connector (left black 8 pin connector) carries RS232 and other signals. The unit transmits logged data on its Tx line [pin 3 - RJ45] and receives commands (from PC or display) and code updates from a PC on its Rx line [pin 2 - RJ45].

The diagram at left shows the wires within the cable and also the connections at each end. Note the pin names change from left to right - the WB unit's Tx pin transmits to the PC's Rx pin (and vice versa). [pin 5 - RJ45] is the shield for the Rx and Tx data lines as well as being the return data path.

WBo2 to PC cable

Here's an image of the actual RS232 cable for connection between a PC and the WB unit. The cable is used for either logging to a PC, or for re-flashing its code (under control of a PC). If you need to extend the cable then a standard straight through male-female DB9 extension cable should be used (ie. not a cross-over or null modem cable).

The SV_out [pin 1], WB_lin+ [pin 4] & NB_sim [pin 6] signals are all described in detail above. The SV_out signal is intended for analogue displays like the LD01 and those displays will also use Vbatt & GND described below. The RJ45 connector signal names are shown at right.

A fused, protected and partially filtered battery voltage V_batt is available from [pin 8] (right most RJ45 signal). This output is provided to power other devices such as the LA1 display or the LD02. It should only be connected to devices that will draw small currents; typically less than 100 milliamps. Excessive current consumption may cause heating of an internal dropping/protection resistor.

A ground GND point [pin 5-RJ45] is provided as a return for the RS232 and Vbatt connections.

Note that there is one unconnected output (N/C = No Connection) on pin 7 of the RJ-45 connectors.

Tacho Input - RPM_coil (Pin 10/10) & RPM_lo (Pin 9/10)

2E0 has a single RPM channel that is captured for logging. Two inputs are provided, one for direct connection to a COIL (or a Tach signal as generated by some vehicles) and another for a lower voltage "logic level" signal as is generated by some sensors. Only one of the RPM inputs can be used at one time. The image at right (click to enlarge) shows the location of VR1 inside the 2E0 case. VR1 can be adjusted to reject high frequency noise signals that sometimes interferes with RPM capture.

The RPM COIL input [pin 10/10] normally connects to the wire going between the points and the COIL. On vehicles that have electronic ignition and a distributor, you would connect to the point between the transistor switch (or ignition amplifier) and the coil. The COIL input should never be connected to any voltage larger than 12 Volts or damage to the WBo2 unit may result.

The RPM Lo input [pin 9/10] can be connected to any lower voltage signal that produces a 5 volt pulse at some small multiple of the engine's revs. Unfortunately the loading (low input impedance) of the Lo input sometimes makes it infeasible to connect to sensitive circuits such as an inductive crank angle sensor.

When the unit first power up, the Tech Edge logo display should be seen for about two seconds. This gives an indication that power is on and the processor is working.

Normally the unit will then go into heating mode with the screen shown. This should last for 20 to 30 seconds. Longer periods may indicate the sensor is being cooled excessively, or the battery voltage is relatively low.

If the sensor has a major mechanical failure, or the sensor cable is unplugged (or damaged), then the Heater Open error may be displayed.

If the sensor cable is shorted (or the sensor damaged), then the Heater Short error may be displayed.

If the control unit's heater driver FET is found to be non-functional then the Heater FET error may be displayed.

A more common possibility is when the battery voltage is so low (less than approximately 10.5 Volts) the unit cannot power the sensor. In this case the Battery Low condition is displayed. If this occurs regularly then check your wiring or power take-off point.

Similarly, when the battery voltage is too high (above about 19.5 Volts), the Battery High display is shown. In both these battery conditions, the amber LED on the side should be very briefly flashing on, but will appear dim. This condition can be caused by a faulty alternator or loose battery terminals and should be investigated immediately.

During normal operation when the sensor detects a very rich condition that it cannot give a reliable AFR for (around Lambda=0.6 or richer) the Rich indication is displayed.

Similarly when the sensor detects a very lean condition (around Lambda=3.0 or greater) the Lean indication is displayed.

Normal operation will produce either the Lambda or AFR display. The AFR display with two digits to the left of the decimal point is shown.

Pressing the FUNC button changes to the Lambda display as shown. There is one digit to the left of the decimal point.

Holding down the FUNC button for at least 6 seconds will force the current display to become the default power-up mode. To show the mode has been changed, the display will briefly display EE.

Other displays that can be shown are the "OFF" screen when Test Mode 0 is entered, or ...

... the "CAL" screen when Test Mode 2 is entered. For more details of these modes see the DIY kit section.

2E0 does not store data on-board like other WBo2 models. But a serial data stream (described here) is available to be logged to a PC or other RS232 device. Logging software for Win32 and other platforms is available right now.