2A0/2A1
Tech Edge 2A0/1 Features
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The 2A0 and 2A1 is no longer available - refer to the newer and improved controller on the 2Y pages. Please note that we still support our products and provide a repair service - refer to the warranty page. The rest of this document serves as a manual for the 2A0 and 2A1 contrllers (there is no other user manual).
The Tech Edge 2A Wideband unit is housed in a tough ABS plastic case. On the top of the 2A0 case is the logger button and the three status LEDs. The 2A1 adds an extra logging activity LED (see images below). At the end of the case is the green 8 pin logging connector which is a two part removable design. Note : nothing is required to be connected to logging connector for Lambda/AFR sensing. 
The other end of the case carries the RS232/display connector (RJ45), sensor connector (circular 8 pin), and power (PWR, GND). The sensor cable comes in standard lengths of 2.6 or 4.0 m and is specific for each of the sensors types supported because each sensor uses a different physical connector. Any of the Tech Edge displays (analogue LD01, digital LD02 or LA1, etc.) will connect to the RJ45 connector.
In all respects, other than logger memory size, the two units are physically identical. Software developers should also note that the 2A1 stores logged data in sessions that can be extracted individually from the unit, more information on this is in the logger technical section. |
2A0 Connection Overview
The image at left shows how 2A0 is connected to other WBo2 wideband components. Popup images (requires Javascript to be enabled) of some 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 2A0 unit. 2A0 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 & RS232 logging) and for optional connection to an intelligent display. The top of the case has a single button to control on-board logging. There are also three LEDs for power (GREEN), operational (RED) status and heater (AMBER). The other end of the case carries an 8 pin green pluggable connector that carries all the logged input connections. The connectors and their inputs & outputs are described in detail below. Also see the brief connector summary. |
Technical Overview | Outputs | Inputs | Jumper-shunts | LED Diagnostics | Logging
The 2A0 unit, without cables, weighs just over 200 grams, and the case measures 150 x 80 mm with height of 30 mm. The connectors at the back plus front combined protrude a further 15 mm. The on-board logging button on the top protrudes a couple of mm. Sensor, power and display cables are compatible with other 2.0 units but the green pluggable logging connector is assigned differently to other units. The connectors are shown in the images below.
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Left end of 2A0, Y2. )
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Right end of 2A0, Y1, Y3 & Y4. )
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Click on each image to obtain a schematic view of the connectors or see the brief connector summary.
RJ45 (Y1) Outputs - SVout, NBsim, WBlin+, GND & Vbatt
As 2A0's major function is to measure AFR (or Lambda), the unit provides three (3)
software configurable 0 to 5 volt outputs
(WBlin, SVout & NBsim) that can be mapped to the the currently sensed AFR.
The wideband signals SVout [pin 1], WBlin [pin 4] & NBsim [pin 6] signals are all described in detail below. A fused, protected and partially filtered battery voltage Vbatt is available from [pin 8]. 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] is provided as a return for the RS232 and Vbatt connections. The RS232 signals themselves are on Rx [pin 2] & Tx [pin 3]. The WBVout [pin 7] represents the raw buffered Ip current but is not that useful as it is not calibrated to any standard and is not described further. |
WBlin Pin 4/Y1 (on RJ45) Wideband Output
The most accurate of the 3 voltage outputs is WBlin which is generated by a precision 12 bit DAC using a 65 word lookup table (with linear interpolation). The 2A0's WBlin is single ended and requires an earth return via pin 5/Y1. (other WBo2 models have a 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. 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. Unless you have a crimp tool, it can be difficult to use the WBlin output, so there is available the RJ45 Splitter which is described here that makes the signal available via a screw terminal. An alternative to the splitter is to buy a network cable and cut it in half to make a raw ended cable that plugs into Y1. As well as WBlin the SVout & NBsim outputs are available. They use a 10 bit PWM circuit which is less accurate (WBlin is 12 bits) and slightly noisier too. Both outputs can be re-programmed using the Config utility. |
SVout Pin 1/Y1 (on RJ45) Compatibility Output
The SVout signal is intended for analogue displays like the LD01. To generate SVout, 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. |
NBsim Pin 6/Y1 (on RJ45) Simulated Narrowband Output
A synthesized narrowband (NBsim) 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). 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. Unless you have a crimp tool, it can be difficult to use the NBsim output, so there is available the RJ45 Splitter which is described here that makes the signal available via a screw terminal. An alternative to the splitter is to buy a network cable and cut it in half to make a raw ended cable that plugs into Y1. |
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The 2A0's RJ45 connector (Y1, left connector oat the end) carries RS232 and other signals. The unit transmits logged data on its Tx line [pin 3] and receives commands (from PC or display) and code updates from a PC on its Rx line [pin 2]. 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] is the shield for the Rx and Tx data lines as well as being the return data path. |
WBo2 to PC cableHere'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). |
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Analogue Inputs USER1, USER2 & USER3
The left three pins of Y2 are the three 0-5 Volts single ended analogue inputs (USER1 through USER3). They can be used for sampling voltages such as TPS (Throttle Position Sensor) and MAP (Manifold Absolute Pressure), but remember that the measured voltage should not exceed 5 Volts. They are not suitable for measuring pulse inputs unless the pulses have been processed by an external circuit. The USER voltages are sampled at a resolution of 10 bits at a rate determined by logging configuration parameters (default 10 sample/sec). The 3 channels have at least a 10k ohm input impedance. The 10 bit resolution means variation as small as 5 milliVolts can be detected, but in practice the noise limit sets the resolution to as low as 15 to 20 milliVolts. The diagram at left shows how to connect the two possible types of inputs to the USER inputs. The Single Ended Input positive signal wire (+) goes to one of the input pins (Pin 8 = USR 3 in this case), and the return path for the signal is via the vehicle's wiring. The Floating Input positive signal wire goes to another input pin (pin 6 = USR 1 in this case) and the return path for the signal is via the GROUND pin (pin 5) rather than vehicle's wiring. Note that unterminated inputs will float and may show a voltage level when not being used. Either ignore this effect or physically connect all unterminated inputs to GND (pin 5) with short pieces of wire. |
Thermocouple Inputs TC1, TC2 & TC3
The right most 3 pins of Y2 are three single ended thermocouple inputs. There is a single thermocouple amplifier (with a 3 input MUX or multiplexor) that amplifies the very low level thermocouple signals (voltage gain is 101 times). The K type thermocouples used allow a temperature range of ambient to just over 1,200 °C (The actual voltage input is in the range 0->49.5 milliVolts). 2A0 also has an internal thermistor that is used to measure ambient temperature so that ice-point compensation can be applied to the raw thermocouple data to give better accuracy. There are two types of thermocouples; ones with two terminals and one with a single terminal that is used with a ground return. Both types can be used although only the double ended (or floating) one will give noise free results in an automotive environment. The floating thermocouple is attached between ground and the signal input (see image at right). Some thermocouples have screw or bolt attachments and use a single wire. These will work but they will be noisier than a two wire thermocouple. We don't necessarily recommend these people, but http://www.exhaustgas.com should be consulted to give you an idea of what's available. Check their part number 4018-48-R-W (48 inch long wire, weld on bung, stinger model). Or for their probes look at the bottom of the page for the products they make to suit Westach instruments. All of these probes are manufactured with terminals which suit the green connector really well. The image shows the (+)ve terminal insulated with heatshrink. The tabs on the EGT probe's end wires have been "streamlined" to prevent hitting each other during operation. The K-type thermocouples are made in either a clamp-on style, a weld-on style, a high quality bullet probe, or the stinger probes (2 year warranty). Their bullet probes work on 1000 hp/cylinder top fuel cars and need to last 100 passes. Here's a pop-up image of a hose-clamp style EGT clamp. Thermocouples generate a voltage that depends on the difference between the "hot" junction where two dissimilar metals are joined, and the "cold" junction. Basic data for K-type thermocouples is available from NIST at http://srdata.nist.gov/its90/main/its90_main_page.html. 
Conversion of all TC to Analogue Inputs (0-5 Volts)(Note Sept 2006) - Converting all three thermocouple inputs into analogue (0 to 5 Volt) inputs can be done, but it's not possible to have a mix of thermocouple and analogue - it's all or none! Simply remove R409 (100k, 1%) and replace with a wire link. Remove R410 (1k, 1%) and don't replace with anything. This conversion to the board is shown at left (area is near the 8 pin green connector). Refer to the 2A0 DIY construction INDEX page (and the 2A0 overlay [GIF]) for more hardware specific information. Logging software will also have to be told of the change by reconfiguring it. |
Tacho Input - RPMCOIL or RPMLO (Pin 4/Y2) & Shunt J4
2A0 has a single RPM channel that is captured for logging. Although there is a single physical RPM connector (pin 4 Y2) two inputs (COIL & LO/RPM) are provided via the internal jumper shunt J4. Refer below for details of locating and setting J4. Diagram at right shows routing of RPM input to J4 which can be in one of two positions :
RPM Noise Filtering [C401 & VR1]A feature of all 2A0 revisions are the components C401 (470 nF capacitor), and for Rev-3 and above, VR1 (5k preset variable resistor). Their physical location at the bottom left of the board (beside the green connector) is shown here for both Rev PCBs. All 2A0 RPM circuits us a a high pass filter component - capacitor C401. C401 is supplied as a 470 nF capacitor (or 0.47 uF) and is marked as 474, and is usually a small yellow capacitor (but may be dark blue). On some vehicles (using the COIL setting for J4) C401 may limit the maximum RPM that can be logged. C401 can be removed entirely or replaced with a smaller value. Rev-3 and above PCBs include the option of variable resistor VR1. In practice VR1 is not that useful in filtering high frequency noise so VR1 is not normally included on PCBs and a link shown here replaces VR1. |
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2A0 Jumper-Shunt LocationsThe following sections describe how hardware options are set using on board jumper-shunts (often just called jumpers). These shunts are :
Click on the image or here for an enlarged popup of the jumper-shunt locations. |
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Cal Jumper [J1]During all normal operation the J1 (CAL) jumper should be installed. It is shown here as a photo image or as a board view. It is located at the top of the board beside test points TP3 & TP4. Unused Jumper [J3]During normal operation, the J3 jumper should be in the 1-2 position. It is shown here for both Rev-2 and for Rev-3 & above PCBs. It is located in the top left corner of the PCB. Reflashing - Firmware Updates [Y5 pins 2-3]As mentioned in the software section, the reflash utility is used to update the 2A0's firmware (or operating software). The rescue jumper is NOT normally required to be used, but some early models had a bug in their firmware that made using this jumper mandatory for the first reflash. The image at right shows the location of the rescue-reflash jumper-shunt. There is normally NO jumper in the 2-3 position when the unit is not being re-flashed. To perform a rescue-reflash take off the CAL shunt (J1) temporarily and place it on the top two pins (pins 2-3). The location is popup image, and the shunt is placed over both pins to enable the rescue mode. Don't forget to remove the shunt afterwards and replace in the J1 position. |
NTK UEGO & Bosch LSU Support [J-NTK])
The 2A0 has hardware support for both the NTK UEGO sensor (L1H1, L2H2 & related models) as well as the Bosch LSU sensor (all LSU 4.0 & 4.2 models). Go here for more information on the sensors supported by 2A0, but remember the sensor's actual connector may be different between otherwise compatible sensors. To change the sensor between UEGO (NTK) and LSU (Bosch), two things must be done:
Note 1: (a) If you have an earlier model 2A0 PCB (most non-DIY 2A0's were rev-4 PCBs), then note: On the Rev-2/3 PCB the resistor R214 must be physically swapped when changing between NTK and Bosch sensors
(NTK UEGO sensor uses a (largish) 82k resistor for R214, but the Bosch LSU-4.2 sensor uses a much lower value 910Ω resistor).
Note 2: Be very careful to match the J-NTK jumper shunt's position correctly as using the NTK setting with an LSU, or vice versa, may damage the sensor or the 2A0 control unit. This warning is particularly relevant if you swap from LSU to NTK. |
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COIL/RPM-LO Selection Jumper [J4]The J4 shunt, shown at right (and described above), is used with a 3 pin header (Rev-3, Rev-4, etc.. PCB). However J4 was originally a 5 pin header, and this is shown at left. Here's a schematic for both versions of J4. See above for details of the C401 filter capacitor and VR1 variable resistor that can also affect RPM logging. |
Operation of the LEDs (Power, Heater, Status)The unit has three LEDs. Their Normal operational status is described below. From left to right the LEDs are :
Diagnostics from the RED & AMBER LEDs
Unlocked PID : It's possible for transient conditions to cause the RED LED to flash off briefly. As long as the AMBER LED and green POWER LED remain on then this is an indication of a PID unlock condition. A PID unlock is not necessarily an error, but it does indicate either very rapid changes in heating or cooling of the sensor, and/or rapid changes in the ambient air-fuel ratio. If this occurs without an explanation (such as rapid changes in throttle position) then it may be an indication of an intermittent somewhere in the wiring, or an aging sensor. Both the LD02 and the TEWBlog logger indicate these conditions. 
The heater PID sharp single OFF flash is shown and prior to rev firmware Rev-48 this single OFF flash was also used to indicate a wideband PID unlock too. This condition indicates may indicate the sensor is positioned where it is either too hot or too cool.
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Serial Logging, Logger Button and & Software
2A0 stores data on-board as well as the normal power-up mode of sending a serial data stream to be logged to a PC or other RS232 device. 2A0 can be commanded to save data in on-board mode by operating the logger button shown at left. All inputs, analogue, thermocouple and RPM, as well as AFR are logged. The RED status LED serves double duty during logging by indicating the current logging mode when it is enabled.
On-Board Logging :
The on-board logging memory is a 32k byte EEPROM buffer that stores over 1,150 frame of 28 bytes each.
At a logging rate of 10 frames/sec (the default) that's about 115 seconds
Serial PC Logging & Software : Direct and unlimited logging from the serial RS232 port to a PC or handheld device is performed by default. This allows WBo2 to log and store a virtually unlimited quantity of information. Win32 and other platform Logging software is available right now. On-board logging is also controlled by the LA1 or LD02 intelligent display. These displays have a single button that turns on-board logging on or off with a single press. |
Logging Button Operation & Red LED Logging StatusA combination of short, medium, and long button presses commands the on-board logger to enter one of three states - Stopped, Enabled and Logging.
Further InformationGo here for the additional features of 2A1. We update 2A0 documentation from time-to-time in response to your Feedback. |
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As well, an RS232 data stream provides digitally precise information on sensed AFR and all logged inputs.
These outputs are described in detail in the following paragraphs.
Note: Pin 3/Y1 refers to pin 3 on the 8 pin RJ45 connector Y1.
2A0 has a green 8 pin 
Normal Operation :
The unit should always have a steady RED LED (unless on-board logging is active - see below).
The AMBER LED is brightly LIT but will flicker at 30 Hz (just perceptible).
The intensity of the AMBER flicker will give some idea of how much power is being used to maintain the heater's temperature.
Normal - Heating :
Just after the unit has been turned on the normal heating cycle will cause the RED LED
to flash about once a second with a short sharp ON time, and longer OFF time.
The AMBER LED will produce a small amount of flicker (30 Hz), but should be brightly LIT.
This should last 20 to 30 seconds for a cold sensor.
If the time is much over 30 seconds then either the battery voltage may be low
or the sensor is placed where it is being excessively cooled by the gas flowing past it.
A cool sensor position may result in reduced sensor life and inaccurate measurements.
Error - No Heating :
If the sensor cable is disconnected or damaged,
the battery voltage too low or too high,
or some other problem with the heater circuit occurs,
the RED LED will flash with a fast regular ON - OFF beat twice a second
While these conditions remain the AMBER LED will be mostly DIM
but will produce a very sharp flicker a few times a second
(the unit is looking for sensor or sampling battery voltage).
This condition can occur during starting or when there is excessive battery drain during idle.
It may be an indication of a poor battery or alternator/regulator, or connection to the wrong point of the vehicle's wiring.
A wideband PID is now indicated by a sharp double OFF flash as shown here.
If you have earlier firmware and need to differentiate between the two conditions
then download the latest 
or just less than 2 minutes. The Logging rate can be varied up to around 50 frames/sec (23 seconds of logging)
or down to less than a frame every 2 seconds (about 40 minutes). Logging 
slow flash (on-off every 2 seconds) = enabled for logging.
double flash (two flashes every second) = logging.
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