Wow @t3p3tony... this was really useful. I made the following changes in the config and it worked... Duet surprises me every day... It has solved my problem for now

M92 X640.00 Y640.00 Z3200.00 E200:200:200:200:200 ; Set steps per mm

; Tools
M563 P0 D0:1:2:3:4 H1 ; Define tool 0
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

The Gcode that I tried is;
G1 E10:100 :200:300:400
and the motors (E0, E1, E2, E3, E4)danced along.
I tried 5 extruder motors just out of curiosity

What is the layer height that you are printing with.. it can so happen that the extruder is pushing more that what is coming out and pressure is building up in the extruder.

Also check your layer change and retraction settings in the slicer. probably layer height change is taking a long time.

you can also read through the gcode that is generated and check for unwanted codes or change in feedrate.

I read a few posts that talk about peltier heating OR cooling and also found one post that talks about both together but I believe it is still incomplete.

i know i need to use a relay to switch on and OFF the peltier and a DPDT/H-bridge to switch polarity on the peltier.

But on the firmware side, i am new with 0% programming knowledge so i need some help there. I read on one post, where David said its not in Heat.cpp but in pid.cpp

https://forum.duet3d.com/topic/5057/reverse-polarity-of-heater-peltier-heating-cooling/31

But what next.???

i am just making sure i don't fry the board by doing something wrong

my doubt is whether this can be done;

and if i wanted to connect two probes can one more be connected in the E0 endstop STP pin for the U axis?

Then i tried using theProbe for the U axis and i made this tiny change in the config.g file;

; Endstops
M574 X1 Y1 Z1 S0 ; Set active low and disabled endstops
M574 U1 S2

And that too worked fine

Ok so i did connect a Zprobe and got it working. I made the following changes and it worked for the NPN inductive sensor that I scavenged.

I made the following wiring. I used the IN4007 because i dint have anything else on me.

The following config changes were done;

**; Endstops
M574 X1 Y1 U1 S0 ; Set active low and disabled endstops
M574 Z1 S2

; Z-Probe
M558 P1 I1 H5 F120 T6000
M557 X25:0 Y25:0 S20 ; Define mesh grid**

and it worked fine.

ok then im safe... my hardware says Duet2 V1.04... yippie

mine says;

M115
FIRMWARE_NAME: RepRapFirmware for Duet 2 WiFi/Ethernet FIRMWARE_VERSION: 2.0(RTOS) ELECTRONICS: Duet WiFi 1.02 or later + DueX5 FIRMWARE_DATE: 2018-06-05b3

so I guess it's not compatible!

so even a capacitive probe, working on 12V will not harm the Duet if the signal pin of probe is connected to any endstop STP pin.

what about on the hardware side... where can i put the additional probe pins?