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Steer Position Zero. Value ?

3K views 13 replies 5 participants last post by  cornhusker2 
#1 ·
Would some be able to provide me some guidance on the steerposzero variable within the code? I am using the pcb with the Delphi steering angle sensor. My raw value is around -40000. Does that sound right? I can’t get it to zero out even with making software adjustments. Could you please advise me what value to put in the codes so I can get this to work? Thanks
 
#2 ·
Oh something is wrong because even at 15 bits single ended 16,000 should be about the middle. As in if the sensor is putting out 2.5 v times 0.6666 (gain is set to 2/3) is 1.67 volts which is 1.67/5.0 of the way to 32,000 which is around 11,000.

Clear as mud i bet.
 
#3 ·
Please note that I’m only referencing the raw data from sensor number. I was able to get a different number to roughlyt 100 or so by changing the Steer angle sensor zero and Counts per degree. This is the first number that shows in a series of 5 numbers separated by commas. I’m not 100 percent on what all of these numbers represent.
Thanks,
 
#5 ·
It sounds like maybe a rotational steering angle sensor is being employed like may be used in a modern automotive design?

Unfortunately a large amount of agricultural equipment uses a single steering cylinder with no compensation for reduced cylinder volume on the shaft side of the piston. In that case the degree counts would be very considerably different to actual wheel headings depending on whether the steering wheel is being rotated left or right from lock to lock.

I’m shutting up again now. Carry on boys.
 
#6 ·
If you are using a very unique pcb with a sensor no one has really tried, it will be very difficult to help without links etc to what you are using. Are you sure it is even an analog output? Which Delphi sensor? And which pcb?


Normally you only need 5v and a gnd to power the sensor. Then the output of the sensor from 0 to 5v goes to high input. The low does not require a connection.
 
#7 ·
I attempted to use my own WAS several months back with no luck. I changed gears and decided to use Brian's AutoSteer PCB design and the Delphi ER10031. Page 27 suggests to hook it up using 4 connections on the PCB. The low and ground connections go together. The rest was the same. Is that no longer the case? Thanks.
 
#8 ·
The delphi has the 3 connections. Hook the +5v to the +5v. Hook the ground to the board ground - not the "Low". Hook the delphi output to the high of the ADS1115. There is no connection required to the "low".



Verify with a voltmeter on the output of the sensor you are getting around 2.5v from the Delphi out when the wheels are pointing straight ahead.
 
#11 ·
The directions say to adjust the steerpositionzero up or down if you can't get the steering angle to zero out when configuring. The only area that this variable is mentioned is with these settings:

steeringPositionZero = 1530 + Serial.read()

The think I have a gain issue, but still don't know how to resolve it. As Brian suggested I will measure the voltage on the output pin when I have the steering wheel in the straight position and look for 2.5V. I plan on posting my results yet this week unless anyone else has other suggestions.

Thanks,
 
#12 ·
Everything has to work together. The 1530 plus the number you set in settings subtracts from the 3000 and some at full scale to give you a zero reading when straight ahead, -1500 when turning left and +1500 when turning right. You need all those numbers to be right.
 
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