Using the Del-Sigma A/D on the CYC8kit-5LP at 8 bits,  but when increasing to 10 bits or more, the error increases.

I'm using a UART to display measurements to a terminal

The component is configured as:

If my input is  4.002V (accuracy  +- 1mV) ,  

Then with A/D  spits out 4023 mV.  which is within 1LSB of error.  

Change the A/D to 10bits and the A/D gives 4053mV 

Change the A/D to 12 bits and I get : 4061mV

14bits gives 4063mV.

Any Idea as to what I'm doing wrong?

PSOC model used: CY8C5868AXI-LP035
The relevant parameters of the crystal oscillator need to be set within the program Human attachment Picture:

Question: ① Should the settings of the red circle in the picture be set according to C0 and CL in the selected crystal oscillator data sheet?
② How much impact do the C0 and CL parameters set here (if not set according to the crystal data sheet parameters) have on the normal operation of the entire程序设置界面 system? Program settings interface

I am connecting a resistor to the DAC output and I am giving sine wave current signal to it of 1 khz freq and 5 micro amp  for 10 times. every time I give this signal for 1 sec. I first start signal generation ,  on this for 1 second and stop signal. give some delay and repeat this process. 

 But every time when I start the signal I found a Spike at the resistor. Why this is coming, and How can I remove it? 

2 hours ago, the drop down forum menus were working.

Now, there are no drop down menus.  I have to keep going back to Infineon homepage in order to get to the forum I want.
I had to choose a Forum from this form, but the problem is with ALL the forum drop down menus.  They're non-existent.

Running PC with Win10, MS Edge.

How about back tracking to the previous release of the forum software!!!  It worked well enough to use.  The current release is not usable.

I'm using readings from a Sigma Delta ADC as the control variable for a PID loop. It's reading across the sense resistor in a FET based current source. The gate voltage on the FET is process variable.

When I just feed a voltage into the ADC, I get accurate readings. However, as soon as I include the FET and current sense resistor in the circuit, I get bogus readings. The output of the system is stable, it's just at the wrong current. The ADC reads the control variable's value as equal to, or close to, the setpoint, but my actual output is off by as much as 200%.

I've been playing with this for a couple of days and I can't figure it out. The project is attached...If anyone can give me any insight into this, I'd be much obliged.

Mike