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3.2
Operating Modes
The CMOVE 1250 works in the following operating modes:
•
Pressure (pressure control mode)
•
Flow (gas flow adjustment mode)
Pressure control (Pressure)
This operating mode is used for controlling the pressure in a vacuum system either with a
variable gas flow (upstream control) or with a variable conductance (down-stream control).
Any of the implemented gauges (see chapter «12.1 Implemented Pressure Sensors»), or
another appropriate pressure sensor and a suitable control valve are required for this mode.
The pressure sensor supplies a continuous pressure signal (0 … +10 VDC) to the
CMOVE 1250. The CMOVE 1250 compares the pressure signal (actual value) with the
nominal pressure and controls the control valve in a way which compensates for the
dynamic characteristics of the controlled process. This means that the actual value should
attain the setpoint (nominal value) as rapidly as possible and then fluctuate as little as
possible about it.
The setpoint (nominal value) can be entered manually on the Pressure Controller or
provided by an external control system.
Control modes
The CMOVE 1250 can be operated in two control modes:
STD:
Pressure control with variable gas flow (upstream control):
The control valve regulates the gas inlet of the vacuum system. The valve
plate moves in closing direction when the pressure in the vacuum system
rises.
Figure 3-2
Vacuum pump
Pressure
sensor
Gas inlet
Vacuum
system
Valve
CMOVE 1250
