Pulsing Output; Understanding Pulsing - Advanced Energy Paramount MF 2 kW User Manual

®
Advanced Energy
Table 5‑7. Frequency tuning parameters (Continued)
Parameter
Tuning step time Sets the amount of measurement averaging time before
the automatic tuning algorithm makes a frequency
change. You cannot change this parameter while the
RF output is on.
Gamma threshold This command is not active
mode

PULSING OUTPUT

Understanding Pulsing

When pulsing is enabled, the Paramount MF 2 kW generator pulses RF output on and
off based on frequency and duty-cycle settings:
• The frequency defines the length of pulsing cycles, that is, the time from the
beginning of one RF on event to the beginning of the next RF on event.
• The duty cycle sets the percentage of each pulsing cycle for which output is on.
If either frequency or duty cycle is set to zero, pulsing is disabled.
An RF on event during pulsing is different than an RF on event when RF is enabled:
• When RF is enabled, the generator starts with the lowest power level and then
ramps up the power until it meets the set point. The ramp up process lasts about
8 ms and is too slow for pulsing.
• During pulsing, when RF turns off, the generator remembers inverter settings.
When the next RF on event happens, RF comes on with the same power setting
as the end of the previous pulse. Power control loop becomes active 150 μs after
the start of the pulse, when the pulse transient process is over, and regulates
power until RF is off again. Then all settings get frozen until the start of the
next pulse.
This way of turning RF on and off allows for the much faster pulsing, but at the same
time it results in more transients and overshoots. To minimize transients, RF always
turns on and off in the correct phase of the RF clock. When an internal circuitry
command comes to start the next pulse, the generator waits up to one RF cycle for the
correct phase of the internal RF clock, and then starts in this phase. The same event
happens when the generator receives another internal circuitry command to end
pulse. As a result, RF on length could be more than programmed by up to 2.5 μs. RF
off length also could be longer than programmed by up to 2.5 μs.
For master/slave pulsing, the rear SMA Sync Out connector on the master unit
should be connected to the rear SMA Sync In connector on a slave unit, using a coax
cable. The slave unit receives a signal (PSYNC) from the master, and then matches its
57020114-00E
Description
Installation, Setup, and Operation
®
Paramount MF 2 kW Generator
Command
Set: 118,
subcommand 22
Report: 248,
subcommand 22
n/a
5‑27