MKS Instruments UK Ltd
V2000-C/E Hardware Manual – SP102005.102 March 2013
31
Maintenance
Vision 2000-C/E systems require periodic maintenance largely due to the effects of exposure to corrosive
process gases. The frequency of minimum maintenance is, therefore, dependant on the application. Most
commonly (approximately 12 months), the turbopump will require bearing lubricant exchange and the filaments
will need to be replaced. The ion source might also need to be rebuilt at this point. Less frequently, the electron
multiplier will be replacement (when gain can no longer be adjusted to be sufficient). The inlet gauge zero offset
should also be checked
Systems configured for a very low V1 inlet pressure (< 20 mtorr) will require periodic inlet gauge zero offset
correction, especially If the process chamber is vented frequently, or ambient temperature changes.
In general, it is a good idea to schedule maintenance of the Vision 2000-C/E, including preventative measures,
such as renewing filaments, to coincide with planned maintenance of the process system.
Inlet gauge zero
Zeroing should be carried out only with the process chamber at a pressure of less than 1 mtorr,
One gauge system (722 Baratron only)
Connect a DVM set to read DC mV to the two flying leads coming from the gauge connector and measure the
voltage.
Ensure that the process chamber pressure is below 1milli-torr then check the meter reading. If the indicated
voltage is greater than zero, then you should re-zero the gauge:
Remove the grommet covering the zero adjustment potentiometer and using a small, flat-blade
screwdriver, fine-tune until the indicated voltage reads 0.00mV DC (+/- 0.5mv DC).
DO NOT ADJUST THE “SPAN” CONTROL!
Two gauge system (722 and 890 Baratron)
Once the 722 is zeroed, move the meter to the tails of the 890 gauge. Locate and press the recessed zero
switch and check the meter reading is around 0.00mV DC (+/- 0.5mV DC)
Once the gauge(s) has been zeroed, you should immediately zero the Interface Module by pressing the
re
cessed “Zero” button, a tactile click will be felt once pressed.
Operating pressure
As described in Inlet Operation on
, the Vision 2000C/E system has a special closed ion source with an
optimum operating pressure.
Monitoring processes at pressures higher than 5x10
-3
mbar requires inlet pressure reduction. The UniBloc™
inlet is factory-configured to the application requirements specified at time of order. By changing its configuration
and/or internal flow-restricting orifices, it is possible to change its pressure sampling range.
If application requirements change, please contact an MKS representative for information regarding return of the
UniBloc for reconfiguration.
