Varian 450-GC, User Manual

Page: 131 / 205

Detectors
Varian, Inc. User Manual 450-GC Page: 281
The analog output ports are programmed in the 450-GC method by pressing
the DETECTOR key on the keyboard, select Analog Output.
This brings up a menu screen from which you choose one of the three ports to
program; Page 1, Page 2 or Page 3. The following screen appears when
Page 1 is chosen.
The Analog Output Port name is in this example is A, but can be changed in the
Setup screen. The individual analog ports can be assigned to any installed
detector on the 450-GC. The ports are identified as A, B and C with the default
assignment being front, middle and rear detector respectively. Default Analog
output voltage is 0-1 Volt (0-10 Volt is possible by selectable jumpers on the
mainboard (contact your local Varian office).
The right-side of the screen is used to time program the signal source of the
analog output. By default analog output A is assigned to the front detector. In
the example above, the analog port is programmed to transmit the Front
detector signal for the first 10 minutes of the run and then switch to the Middle
detector after 20 minutes the switch will be made to the rear detector for the
remainder of the run. This mode of operation is known as detector switching.
Note that the attenuation should normally be set to 0. However for optimum
resolution (less electronic noise) the best results are achieved by increasing the
attenuation if small peaks are detected. For overloaded peaks decrease
attenuation.