B800-00-880 Issue D
Page 48
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Edwards and the Edwards logo are trademarks of Edwards Limited.
Installation
When the pump is shipped, the controller is configured with the factory default vent option 0, as detailed in
Table 19
.
The controller can be configured to one of the other venting options provided commands can be sent via the serial
interface or an Edwards TIC Turbo and Instrument Controller or Turbo Controller.
The controller only energises (‘shuts’) the TAV solenoid valve when it receives a start command. Prior to that, the
valve will be in the ‘open’ vent state. If the vacuum system is a large system, allow the backing pump to reduce the
pressure in the system to an acceptable level before starting the nEXT pump. In this case, send a command via the
serial interface to close the vent valve before sending a start command - this is known as a delayed start.
If the nEXT pump is being controlled with an Edwards TIC Turbo and Instrument Controller or TIC Turbo Controller,
the TAV solenoid valve can be driven from the TIC. Refer to the TIC Instruction Manuals for more information.
3.9.4
Alternative valve connected to the vacuum system
If using another vent valve, ensure that a suitable vent restrictor is fitted to the vacuum system to limit the rate of
pressure rise. Refer to
Table 20
for information about vent restrictor sizes. If a suitable vent restrictor is not fitted,
open the vent valve only after the speed of the pump has fallen to 50% of full rotational speed.
Table 19 - Vent options
Option number
Description of vent function
0
Vent valve opens fully below 50% full rotational speed for either stop command or
fail.
Note:
This is the factory default setting.
1
Controlled venting from 100% to 50% full rotational speed; vent valve opens fully
below 50% for either stop command or fail.
2
Vent valve fully opens immediately if stop command is received; vent valve opens
fully below 50% full rotational speed if fail.
3
Vent valve fully opens immediately if stop command is received; controlled
venting from 100% to 50% full rotational speed if fail then vent valve opens fully
below 50 %.
4
Vent valve fully opens immediately if fail; vent valve opens fully below 50% full
rotational speed if stop.
5
Vent valve fully opens immediately if Fail; controlled venting from 100% to 50% full
rotational speed if Stop command received then vent valve opens fully below 50%.
6.7
Vent valve fully opens immediately for either Stop command or Fail.
Table 20 - Vent restrictor orifice diameter (with atmospheric pressure at the inlet of the vent valve)
Vacuum system volume (litres)
Orifice diameter (mm)
< 20
1.0
< 10
0.7
< 5
0.5
< 2
0.35
