Open Loop Boost Control

[Sprocket]

I have been asked to install a WBO2 gauge but the customer would also like a user adjustable boost control and is not bothered about the RPM or MAP input.

I have explained that what I am about to discuss here would be no better than an MBC valve (bleed valve), other than having a pre calibrated minimum and maximum boost levels with a visual setpoint indication on the gauge, if it works 


Theory

set I and D in PID settings to zero. Set Analog out voltage out values all to 5.00v. Use analog out volts and ground for 5v refference on 1k potentiometer, with the analog input from the potentiometer wiper. Calibrate boost level DC and analog input to give  the required minimum and maximum boost levels at extents of potentiometer rotation.

This in theory will allow the P element of the PID loop to generate a constant output increase or decrease depending on the refference voltage value against the configured boost target resulting in an open loop control that simply increases or decreases boost as set by the operator.

Obviously careful calibration is required, and the input refference voltage could be calibrated such that it represents boost target as set by the potentiometer, and shown on the guage.

Potential problems?...........................Discussion welcome This is just theory at the moment

[gunni]

You don´t need the analog out channel, that is just for lambda output.

I´d probably use a 5k pot and adjust the rotational travel to equal percentages of the scale, i.e min = min, half way is infact 50% of max and full is max.

So you want to impose a fixed "map" value with a resistor? Then use the pot as the target adjuster, the P will then adjust the DC accordingly?