Operating instructions

CPS:Doc 20017 V1 24/01/2012 Page 14 Issue 1 24/01/2012
Description Of Auxiliary feedback Connection / Function
Auxiliary feedback is typically used in vacuum processes in order to control the dark space bias potential.
The following drawing shows the connections to link the CPS RF generator to a CPS automatic matching
network controller.
Pin 9 Auxiliary feedback -ve. To enable this function connect pin 16 to a ground pin. The feedback signal
should be a negative voltage in the range 0v to –5v. This function is mainly used for plasma dark-space
potential (bias) control.
Pin 10 Auxiliary feedback +ve. To enable this function connect pin 16 to a ground pin. Connect this pin to
ground at the AMN controller
Pin 16 Remote feedback enable. Ground this pin to enable the Pin1 Auxiliary feedback function.
NB. When using the auxiliary feedback facility, if feedback voltage is not present then RF power will rise
to maximum. On plasma systems this is often advantageous as it allows the generator to supply high
power to strike plasma, then cut back to operating level as soon as plasma is struck.
Other functions
Pin 20 +5V. This is a +5V 500mA Output. This may be used as a power source to illuminate LEDS or
power small adapter circuits or displays.
Pin 6 Not Used
Pin 7,8 Ground