Summary of bugs and changes:
Voltage reference IC U4 changes to NCP51460SN33T1G - a 3.3V SOT23
voltage reference, RS part 719-2642
Nand gate IC1 changes to AND gate SN74AHC1G08D8VR, RS part 526-436
R21 changes to 200k, new value of resistor.
R22 changes to 10k, an existing value
R23 changes to NM (not mounted)
The LED changes to L-710A8GE/2LGD-RV (2 green LED's, as the Red/Green
had the wrong Cathode), RS part 616-4116
A flying lead is required from the MAX1932 Pin 12 (CS bar) to Pin 42 of
the Arduino shield to enable the signals for the power supply set point.
In general a fairly good bill of health for the design. Communications
(address ack.) has been checked for both I2C busses, verification of the
I2C device functionality is still on the list of things to do.
Comments as we went along:
Wrong part for the indicator LED (anode and cathode are swapped) - to be
Very hard to get the Arduino off once it's pushed in.
The 4.096V reference is too high. Needs to be changed to something 3.3V
or lower. Precision is currently approx 200mV steps on the trigger
The !CS isn't connected to the arduino - needs pinning out to Digital
Observed Vout from Vbias is 39V; limit value from the Zener. Killed the
HV PSU on board 1!
NAND Gate to be swapped for AND Gate.