PID Selection

[Whodunnit]

Hi there, I noticed that if trending is turned on for certain PID's, the values of others can change quite a bit. I first ran into this when I tried turning on the injector pulse width PID's and saw timing and knock return change drastically.

Does anyone know of any rules of thumb when choosing which loops to trend and how many is too many?

Thanks in advance for your help!

- bret

[Whodunnit]

Hi folks. In the absence of feedback, I did find this in an adjacent thread:


These are the ones I am using:

OK DESCRIPTION CAPTION UNITS SYSTEM CH PARAMETER
Y Calculated Injector Flow Rate (Generic scan mode only) INJFLOW Grams/s,Lbs/Min Fuel 2 GM.INJFLOW
Y Calculated Load Value LOAD_PCT % Performance 1 SAE.LOAD_PCT
Y Cam Phase Angle Desired CAMPA_DES Degrees Conditions 2 GM.CAMPA_DES
Y Commanded Air Fuel Ratio B AFR_B :1 Fuel 1 GM.AFR_B
Y Damped VSS DAMPVSS KMH,MPH Performance 0 CALC.DAMPVSS
Y Delivered Engine Torque to Transmission TRQENG_B Nm,Ft-Lbs Transmission 2 GM.TRQENG_B
Y Engine Coolant Temperature ECT °C,°F Temperature 1 SAE.ECT
Y Engine RPM RPM RPM Conditions 2 SAE.RPM
Y Ignition Timing Advance for #1 Cylinder SPARKADV Degrees Spark 1 SAE.SPARKADV
Y Injector Pulse Width Injector 1 INJ1PW ms Fuel 2 GM.INJ1PW
Y Intake Air Temperature IAT °C,°F Temperature 1 SAE.IAT
Y Intake Manifold Absolute Pressure MAP kPa,inHg Air 1 SAE.MAP
Y Last Shift Time SHIFTLAST Seconds Transmission 1 GM.SHIFTLAST
Y Long Term Fuel Trim - Bank 1 LONGFT1 % Fuel 1 SAE.LONGFT1
Y Retard Due to Knock KR Degrees Spark 1 GM.KR
Y Short Term Fuel Trim - Bank 1 SHRTFT1 % Fuel 1 SAE.SHRTFT1
Y Throttle Position TP % Throttle 1 GM.TP
Y Transmission Fluid Temperature TFT °C,°F Temperature 1 GM.TFT
Y Vehicle Speed Sensor VSS KMH,MPH Conditions 1 SAE.VSS

Here is the link to that thread: http://forum.efilive.com/showthread.php?t=3843