Hypertherm HT4400 HySpeed Plasma Arc Cutting System - Manual (Page 98)

MAINTENANCE
HT4400 Instruction Manual 5-7
HT4400 Plasma RUN Sequence
The following flowchart shows the sequence from RUN state through the end of a cut. Shaded boxes indicate
action taken by the operator.
System in RUN state
¥ Analog board compares output current
of each chopper to the set current
for each chopper
¥ Plasma START input monitored
¥ Phase loss monitored
¥ Interlocks monitored
Analog board adjusts
chopper duty cycle
Actual current too high
or too low?
START signal released?
¥ Plasma cut-flow OFF
¥ Choppers ramp down
¥ Choppers OFF
¥ Shield gases OFF
¥ After 100 ms, post-flow gas ON
for 10 s
¥ Gas console displays CA, Cb or Rd
¥ Error counter incremented by 1
START signal given
during post-flow?
¥ Post-flow stops
¥ START sequence begins
¥ Post-flow finishes its sequence
¥ System idle, waiting for next
START command
Yes
Yes
Yes
No
Yes
Current lost before
ramp down complete?
No
Phase loss detected?
¥ Main contactor CON1 OFF
¥ Gas console displays PL error
¥ All functions disabled until
plasma START signal is released
Yes
Yes