Edwards nEXT730D User Manual

vacuum system volumes in order that the rate of pressure rise remains within the limits
shown in V
ent gas specicaon and vent control data on page 30.
Note:
If a vent res
trictor is used, the me required to vent the vacuum system may be
unacceptably long. The me may be reduced by using a vent valve without a vent
restrictor and waing unl the pump speed has fallen to 50% of full rotaonal speed
before opening the vent valve.
7.2.3 Vent valve control
The TAV solenoid valve can be controlled by the nEXT motor controller or by an Edwards
TIC Turbo Instrument Controller.
The nEXT controller can control the rate of venng, using the vent valve opons in Table:
Vent valve opons. Using this feature the pump can be vented from full rotaonal speed
in a controlled manner that will not damage the pump bearings. Once the pump
rotaonal speed has dropped to below 50% of maximum speed it is safe to hard vent
(open the vent valve fully) provided the backing pump is le on and the backing valve is
open.
To use the nEXT controller funcon, the nEXT turbo pump controller has a 4-pin auxiliary
connector socket on the side of the pump, as circled in , which the vent valve with the
auxiliary connector ed is plugged into.
The controller is capable of controlling a number of dierent venng opons. These are
dened in Table: Vent valve opons.
The controller is capable of accommodang both normally open and normally closed
vent valve types. These are dened in Table: Valve types. A power cycle is required aer
making a change to the valve type, before the auxiliary output circuitry adjusts to
accommodate the requested change.
Table 19 Vent valve opons
Opon num-
ber
Descripon of ven
t funcon
0 Vent valve opens fully below 50% full rotaonal speed for either a stop
command or fail condion.
*
1 Controlled venng fr
om 100% to 50% full rotaonal speed and then
vent valve opens fully below 50% for either a stop command or fail
condion.
2 If a stop command is received, vent valve fully opens immediately. In a
fail condion, vent valve opens fully below 50% full rotaonal speed.
3 If a stop command is received, vent valve fully opens immediately. In a
fail condion, controlled venng from 100% to 50% full rotaonal
speed and then vent valve opens fully below 50%.
4 In a fail condion, vent valve fully opens immediately. If a stop com-
mand is received, vent valve opens fully below 50% full rotaonal
speed.
08/2021 - ©Edwards Limited
Page 77B8J200880_D
300812671_002_C3
B8J200880_D - Operaon

Edwards nEXT730D Specifications

General

Brand	Edwards
Model	nEXT730D
Category	Water Pump
Language	English