Tweco SC-3000 - Manual (Page 61)

SC-3000
Manual 0-5100 4-21 OPERATION
Gas Preflow
Setting on Operator Terminal (OT) used for preflow during height finding. (See "Preflow during Height
Finding" later in this section).When the Operator Terminal Preflow is set to zero plasma preflow will
not start until THC has positioned torch at pierce height. Then gas flows for the full plasma preflow
time, default setting is 2 sec.
Setting Preflow to anything other than zero will activate Enable Ignition Plasma sending signal to the
plasma supply’s Preflow On input (when cable is wired to TB2-3&4 of CCM) to start gas flow at the
same time that Initial Position Start is received from CNC. Gas flow starts immediately and continues
until Separate Ignition Plasma sends Start to plasma. If the time has already exceed the plasma preflow
time (default is 2 sec) then pilot ignites immediately. If time has been less than plasma preflow time,
plasma waits for the time remaining before igniting pilot.
• Set in tenths of a second (0-6.0 sec).
• Set to 0 disables the feature.
• To enable set time to equal the Plasma’s preflow time.
• Used to speed up the cutting cycle time by starting preflow gas at the same time as the torch is
coming down to find height. Must connect separate Preflow Control cable to plasma input to en-
able preflow. See description of using Preflow during Height Finding for details of how to use this
function.
Note
Not all plasma supplies have the inputs to use this feature.
End of Cut
• Set 0-100%.
• For the THC to detect that the cut is finished and retract the torch three things must happen. The
Start from the CNC (Initial Position Start) must be removed, the OK to Move from the plasma sup-
ply must go away indicating the cutting arc has stopped and the measured arc voltage must drop a
% below the voltage it was at while cutting. End of cut (0-100%) sets the % by which the voltage
has to reduce. Default setting is 85%. A lower % will add a small delay before retracting while the
plasma supply’s output voltage bleeds down. A higher percentage will shorten the delay.