Agilent Technologies TwisTorr 305 FS User Manual page 183

Technical Information
This is dedicated 24 Vdc connector to control the optional vent valve (see orderable parts
table). The vent valve can be driven by controller automatically or by serial line.
Three different vent modalities are available on the control unit:
On Command, Automatic, Auto Pump Speed.
On command means that the valve is set to open or closed by the means of a

specific serial command.
Automatic means that the controller acts on the vent valve automatically,

based on the turbo pump working status (Start, Ramp, Stop, Fail, etc..). It
means that the valve is set to open/close, based on the working condition of
the Turbo pump. It is possible to select the opening delay and the opening time
by means of some specific serial command.
The figure shown below is referred to the Automatic vent mode.
Auto pump speed means that the controller acts on the vent valve

automatically, based on the pump status. Compared to the Automatic modality,
the auto pump speed implements a pulsed opening/closing of the valve to
optimize the deceleration of the turbo pump. This vent mode is fully automatic
and hence it is not possible to select the opening delay and the opening time of
the vent valve.
Please refer to the chapter "Technical Information", Window Meanings paragraph in
order to get details about the serial commands related to the vent modes.
Figure 33 Vent Valve diagram in "Automatic" mode
Agilent TwisTorr 305 FS Remote Controller User Manual
Vent Valve
CLOSED
OPEN
RAMP
STOP
START COMMAND
Vent Valve Relay Vent Valve Open
NORMAL
Win. 126
STOP COMMAND
Time Win. 147
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