946 Controller Instruction Manual
pg. 21
•
Pressure readings for all sensors connected to the controller (up to 6)
•
Operational status of MFCs and pressure control valve via the front panel
•
The type of pressure and flow sensor in operation
•
Mass flow rates for all MFCs connected to the controller (up to 6)
•
Relay status (enabled and activated relays are displayed)
•
Pressure control status, including the control valve position opening
•
The operating status of Hot Cathode sensor (active filament, degas)
•
The control status of hot and cold cathode pressure sensors
•
The auto zero channel for Pirani/CP/CM sensors
•
Open position in percent of a pressure control valve
•
System self-checking information (board status, sensor status, pressure range, and etc.)
•
Front panel control lock out is possible to prevent unintended set up changes
Controller operation is straightforward. For example, to access the system setup screen, simply push the
System Setup button and many system parameters can be viewed or changed. The settings of a specific
channel can be viewed or changed by first selecting the channel with the up and down keys until the
green front panel LED on the desired channel is illuminated and then pushing the Channel Setup button.
In addition to the pressure and flow values displayed on the screen, three types of analog signals are
available on the back panel:
•
Buffered analog outputs for each sensor (up to 6). These buffered analog signals respond
immediately to sensor signal changes and can be used in critical fast control applications.
•
Logarithmic/linear analog outputs for each pressure sensor (up to 6) ranging from 0 to 10 V. The
scale for these analog outputs can be adjusted as desired. While these linear signals are
somewhat simpler to deal with than the sensor-dependent buffered analog signals, there is a
longer time delay (<100 msec) due to the signal processing by the microprocessor.
•
There are also combined logarithmic analog outputs available. By combining the sensors with
different measurement ranges (such as Convection Pirani and Cold Cathode sensors), analog
signals with much wider range are available. This eliminates the requirement for
switching/selecting the sensor. The time delay for these analog outputs is around 100 msec.
Twelve (12) mechanical relays with independently adjustable set points allow the 946 to control the
operation of critical components in a vacuum system such as valves or a pump. The set point parameters
are nonvolatile, remaining unchanged after powering down or during a power failure. They may be set or
disabled from either the front panel or RS232/485 communication.
The Controller also has control set points to turn OFF either hot or cold cathode sensors at higher
pressures, extending the operating lifetime before maintenance is required.
Direct computer communication is available to change set up configurations or read pressure and other
information remotely. A RS232/485 serial port is standard, and the communication protocol can be
selected from the System Setup panel.