Edwards nEXT 55, Instruction Manual

Page: 14 / 116

Connect the analogue output to an applicable meter or indicator to display the
applicable system parameter or connect it to the customer control equipment (for
example, to operate other components in the pumping system at set values).
The analogue output can monitor only one system parameter at a time. You can
configure the controller to monitor a different system parameter. Refer to Analogue
signal options on page 67.
2.4.5 Automatic vent options
The manufacturer's TAV vent valve can be connected to the motor controller. The motor
controller can give a number of different venting options and can be configured for a
normally closed and a normally open vent valve.
The motor controller can control the rate of venting. Using this feature, the pump can be
vented from the full rotational speed in a controlled manner that will not damage the
pump bearings. When the pump rotational speed decreases below 50% of the maximum
speed, it is safe to do a hard vent (open the vent valve fully).
Many venting options are available, that include:
▪ Hard vent when the rotational speed decreases below 50% speed.
▪ Controlled vent when the rotational speed is above 50% speed and hard vent is
below 50% speed.
▪ Hard vent immediately through an applicable restrictor.
Controlled venting gives quicker ramp down time by controlling the vent rate through a
single large orifice across the speed range of the pump. A list of the venting options is
given in Vent options, vent valve connection and control on page 72.
There is also a feature that allows a delayed start of the pump. With this feature, the
vent valve can be closed before starting the pump. This allows the backing pump to
decrease the pressure in the vacuum system before starting the pump.
With a ‘Y’ cable adaptor, a TAV and a cooling fan can be controlled at the same time. No
configuration is necessary.
2.4.6 Normal speed setting
The normal speed is a user
‑
selectable parameter which can be set from 50% to 100% of
full rotational speed.
When the pump gets to normal speed, a signal is available on the normal pin of the logic
interface connector. The signal can be used to control the application as it shows that
the vacuum performance (pump speed) is at a set level. The default setting is 80% of the
full rotational speed. Refer to Normal speed setting on page 66 for instructions to
change the normal speed setting.
2.4.7 Electronic braking
The pump has a user
‑
selectable electronic braking option which is disabled by default.
With the electronic braking option disabled, the pump will take power from the
electrical supply during acceleration and operation.
When the pump decelerates it will coast down and power will not be returned to the
electrical supply.
07/2021 - ©Edwards Limited Page 14 B8G000880_E
B8G000880_E - Introduction