TechEdge 2J1 Compatibility
Hi Guys,
I have been playing with a TechEdge 2J1 WB unit and attempting to get the serial connection working with the V2. After some initial work to match everything up I was able to detect the controller and receive serial data from the 2J1. the data however is rather interesting....
After speaking with Peter from TechEdge and reading the details of the unit, I think we need a new protocol set up for the current units ( or perhaps a change to the current V2.0 one ). It seems that the data supplied in the serial protocol changed mid to late 2007 from a 12 bit DAC value, to a Lambda-16 value. details as follows....
http://wbo2.com/2a0/logger.htm
Quote:
Bytes 6 & 7 This is λ-16 (originally Raw Wideband ADC value). In 2007 these two bytes have been redefined to be λ-16 which is fully described here. Originally it was a 12 bit value (0 to 4095) that is applied to the DAC (Digital to Analogue converter) and represents the voltage in mVolts produced by the DAC. The DAC is followed by a amplifier with a gain of 1.00 (for newer version 3 units) or 1.22059(=(68+15)/68 for older version 2 units). Note that the WBlin value is looked up in the WB unit's EE PROM tables using the pump current (Ipx) as index.
the conversion data is.....
http://wbo2.com/sw/lambda-16.htm
Quote:
Lambda-16 is an unsigned 16 bit number representing lambda (λ). For simplicity and to preserve accuracy across the possible range of Lambda, Lambda-16 is a dual-slope transfer function covering the ranges :
Lambda = 0.5 → 5.0 (normal usage range of unleaded AFR = 7.35 to AFR = 73.5)
Lambda = 5.0 → free-air (useful for non-tuning wideband applications)
Lambda (λ) is converted to Lambda-16 (λ16) as follows
If (λ < 5.0)
λ16 = ( λ - 0.5 ) * 8192
else
λ16 = 36864 + (( λ - 5.0 ) * 128)
Lambda-16 is converted to Lambda as follows:
if (λ16 < 36864)
λ = ( λ16 / 8192 ) + 0.5
else
λ = 5.0 + ((λ16 - 36864 ) / 128)
Note that AFR is directly related to λ, and λ16, by
AFR = λ * AFRstoich
AFR = (( λ16 / 8192 ) + 0.5 ) * AFRstoich (for the useful vehicle tuning range)
Where AFRstoich is the AFR value at stoich for the fuel used (14.7 for unleaded).
Any chance of including something in the next update?
Simon.