Hi, I use NCStudio to control my CNC Plasma machine…
The machine has a relay which is connected to the Z axis circuit…
Any Z- drops the head, Any Z+ lifts the head
The relay is also connected to the plasma cutter; and therefore this is turned on with a Z- and off with a Z+
The system works, BUT, Sheetcam does not issue any Z axis commands!?
(Apart from one at the start of the G code file)
Sheetcam also does not use any other commands to start stop the Plasma at all with the chosen post pro file??
(some software like Fastcam use M07 & M08 for example)
So when I nest items and create code, the resultant G code would leave the head down and the plasma ON. Surely this is incorrect?
But, My question is: Can I edit the post processor file so that Sheetcam issues a Z-1.000 command and a Z1.000 command when the head should drop and the plasma should cut??
(A delay after the Z- would be good too!) 
Ok, I think I might have a solution (nearly)
after editing the flashcut plasma post pro file 
and changing the M50 and M51 commands it uses to Z-1.0000 and Z1.0000
Fingers crossed!
N0080 M06 T1 (Plasma, 1 mm kerf)
N0090 G00 Z10.0000
N0100 X130.5000 Y259.5000
N0110 Z1.0000
N0120 Z-1.0000
N0130 G04 X1.2
N0140 G01 X110.5000 F3000
N0150 Y269.5000
N0160 X170.0000
N0170 G03 X170.5000 Y270.0000 I0.0000 J0.5000 F3000.0
N0180 G01 Y425.0000 F3000
N0190 G03 X170.0000 Y425.5000 I-0.5000 J0.0000 F3000.0
N0200 G01 X-0.0000 F3000
N0210 G03 X-0.5000 Y425.0000 I0.0000 J-0.5000 F3000.0
N0220 G01 Y250.0000 F3000
N0230 G03 X-0.0000 Y249.5000 I0.5000 J0.0000 F3000.0
N0240 G01 X110.0000 F3000
N0250 G03 X110.5000 Y250.0000 I0.0000 J0.5000 F3000.0
N0260 G01 Y259.5000 F3000
N0270 X130.5000
N0280 Z1.0000
N0290 G04 X0.5
N0300 G00 Z10.0000
N0310 X209.5000 Y320.0000
N0320 Z1.0000
N0330 Z-1.0000
Just need to lose the extra Z1.0000 commands I think
These Chinese controllers can be configured in various ways so I can’t just write one post to cover every machine. Your mods to the Flashcut post should work. Just have a hunt through the post to make sure there aren’t any other Z axis moves.
Hiya, Cheers, yes I have achieved the desired result!