nanoDLP

Thinking a bit more about this you could maybe use an optical endstop as they generally have a slot which would allow significant Z minus travel after printing( if allowed/set up  in the firmware)

Expand file system can be found in > SETUP > TOOLS  menu
https://drive.google.com/open?id=0B6-jg … E9nQjBQSGs

Why are you running GRBL on a ramps board when there are much more efficient firmwares out there ?? ( Modified Marlin)

First step would be to get firmware loaded onto the 32P8-PU and experiment with that. There are a couple of modified versions of Marlin around and you shouldn't have too much trouble finding something that works. 
From what i gather the modified versions are needed so they "report back" to nano DLP when an action is completed , this to avoid having to include pauses in the process to allow time for an action to complete.
If all else fails a Ramps board would be an affordable solution as you noted

The ramps output that is usually for the PWM fan is D9 and is usually used for the UV LED power supply ( you cant directly connect the LED chip)
It can be controlled with gcode
M106   or M106 S255   = ON
M107 = OFF

Mikhail As per Shahins post it does sound like a limit switch issue . The reason is this. When you power on a machine it has no way of knowing where an axis is until that axis has been homed so it will limit motion until it has homed and hit the limit switch at least once.   From what you have written it sounds like your limit switch is wired wrong or the logic in the software needs changing

Hi
Setup>Hardware>  Shutter Open Gcode & Shutter close Gcode

Hi In answer to your questions
No you cant easily load NanoDLP along side your "normal" Raspi OS
NanoDLP is configured to run in what is called headless mode ...i,e,  it runs without monitor or keyboard. WHen installed it runs the OS and a webserver which is how you access NanoDLP.  It can run either fixed wire connection (on a network) or wireless. I would recommend running it with a cable first then setting up wireless.
If you want to use your Raspi for other things then a second micro SD card with a standard Raspi version of Linux is the way to go. 

Im confident that there is a way to run/ use both on one SD card but if you are just starting out with Raspi ? Nano DLP, then separate cards is a good idea while you gets to grips with Nano DLP

You are welcome.
That video is a part of the series https://www.youtube.com/watch?v=Laq8eov … oY0O9QIQyF

While many of the videos may not relate to your issues they are still worth watching as there many good tips and methods in there.

so on your router you can see which IP has been assigned to your raspi ??
you can download putty and ssh into the raspi ( connect to its IP address) this will give you a terminal screen where you can edit the network config files if needed.
what printer are you trying to connect to??

Hi
See image for the wiring diagram for a ramps >

1/ All 3 jumpers are installed under the stepper driver to give 16 micro steps
2/ Having your stepper driver set to reference voltage 0.8 VDC should give approx 1 amp to drive the stepper which should be more than enough for a simple Z axis
3/ Note the end stop micro switch is connected to "-" & "S" and is wired to be NC-normally closed . Be careful to connect to the correct pins on the ramps !!!
4/ You don't say what printer/ set up you have but in my case the PWM out is connected to a UV LED and is controlled by the G code >>M0106 S 255 for ON & M107 for OFF

You should load the Mega / Ramps with patched firmware >>https://github.com/mUVe3D/Marlin-mUVe1DLP-Running

In Nano DLP you need to set up the motor section as shown >>

The combination of all of these settings should give you the correct build height which you can check
by going to the " Z calibration" page and checking >

( this is based on standard M8 thread with a pitch of 1.25 mm per rotation There is also M8 fine with 1mm per rev Its worth checking what you have) 

Testing
The easiest way to test is to download a program called pronterface (Printrun). Usually for FDM printing it is by far the easiest way to test a ramps board on a printer

http://www.pronterface.com/
WHen installed connect to the ramps with a serial cable
Test the end stop first 
In the pronterface terminal window type M119  This will report the status of the endstops
When you press the Z endstop by hand and issue the M119 command it should report back with "Triggered"
WHen that is confirmed as working you can test the Z motor direction.
Manually move the z axis to mid point ( so its doesn't crash into anything regardless of which direction it moves)
In pronterface click on the Z up +10 mm arrow The print head should move up / away from the build plate
If it moves down then
a/ power off and swap round the Z stepper motor plug
or b/ change the direction in the firmware
When the direction is confirmed as OK you can test the home button.
WHen pressed the print head will lower towards the end stop and trigger it.

Good luck

You are welcome . It just so happens that your issues coincide with my experiments . I had it all working with my top down a few months back but "lost" the SD card somehow. Now im back at reconfiguring from scratch

Z height >>For example i have my Z height at 192000 ( which in my case equates to 120mm of travel)  Why this is expressed as pulses is a mystery to me but there's bound to be a good reason for it
If you set the pluses in the setup screen you can then see what actual distance is by going to the calibration screen and looking under "Platform information"

I too get the erratic movement of the Z axis when in the Z calibration screen. Not sure of the issue there ...probably the stock firmware jerk and acceleration settings . Regardless the motion during a print is fine