Edwards nEXT nEXT85 - Bakeout

When the power is restored aer a power failure, the behavior of the pump depends on
the control mode at the me of failure (parallel or serial) and the duraon of me the
pump was without power. Refer to Table: Behaviour of a pump when the power is re-
instated aer an electrical supply failure on page 80 for number of scenarios.
Table 26 Behaviour of a pump when the power is restored aer an electrical supply failure
Length of power failure Control mode Behaviour of pump
Power is restored before
the rotaonal speed of the
pump decreases below
50%
Parallel or serial
control mode
Regenerave power keeps all output signals
acve during the power failure. The pump will
speed up to designated speed aer the power
has been restored.
Power is restored aer the
rotaonal speed of the
pump decreases below
50% but before
regenerave power stops
Parallel or serial
control mode, mer
disabled
Regenerave power keeps all output signals
acve during the power failure. As the mer is
disabled, the motor controller will go to the fail
condion when the speed decreases below 50%
and will display ashing error code 0. When the
power is restored, the pump will not speed up
unl the error is cleared. To clear the error, send
a stop command (parallel or serial, depend on
the control mode), send a start command to
speed up the pump to the designated speed.
Parallel or serial
control mode, mer
enabled
Regenerave power keeps all output signals
acve during the power failure. If power is
restored before the mer period expires, the
pump will speed up to designated speed. If the
mer period expires, the motor controller will go
into fail condion and will display ashing error
code 3. When the power is restored, the pump
will not speed up unl the error is cleared. To
clear the error, send a stop command (parallel or
serial, depend on the control mode), send a start
command to speed up the pump to the
designated speed.
Power is restored aer the
rotaonal speed of the
pump decreases below
50% and the regenerave
power stops
Parallel or serial
control mode
Regenerave power stops and fails to keep
output signals. When power is restored, the
pump with parallel control will automacally
restart if the start control on the logic interface
is set to start. The pump with serial control
requires a new start command to speed up the
pump to the designated speed. The fail signals
caused during the regenerave power period
are lost when the power is restored.
6.9 Bakeout
If the pump (and the vacuum system) are heated, the degassing process will speed up
and the pump will reach ulmate vacuum in the shortest possible me. Heang the
pump will also prevent condensaon of vapours inside the pump.
Page 80
B8G000880_D - Operaon