Digitel MPC Manual
Page 18 of 72
J112 SER INTFC
(a 9-pin, female Sub-D connector) routes the serial interface signals for the
four serial interface protocols – RS-232, PHI (Physical Electronics), RS-485, and RS-422.
RS-232 Operation
PHI Operation
RS-485 Operation
RS-422 Operation
DCD
1
+TX
2
+TX
2
+RX
3
RXD
2
–TX
8
–TX
8
–RX
7
TXD
3
GND
5
GND
5
GND
5
GND
5
+RX
3
DSR
6
–RX
7
RTS
7
CTS
8
Operating the Ion Pump
Ensure that the pump has been installed according to instructions supplied with it. Install the
DIGITEL MPC according to its instructions.
•
The DIGITEL MPC and pump must be grounded and have a safety ground strap
connecting them to each other.
•
The high voltage cable must be attached to the MPC and the pump.
•
The proper pump size must be selected from the menu mode.
•
The MPC must have the correct output polarity/voltage for the pump.
Note: More power and current are required to start larger ion pumps or pumps started at
higher pressures. Use the full extent of your rough pumping before starting a pump to reduce
pump wear and time to UHV, to improve system ultimate pressure, and to give the most accurate
readings.
To Evacuate the Pump
Before you run an ion pump, it must be evacuated to a minimum vacuum of 1 x 10
–3
Torr.
Details are best obtained from the pump manual, but in general, use the following procedure.
1.
Rough pump down to 1x10
–3
Torr or less (the lower the better).
2.
Ensure that contaminants do not backstream into the ion pump. If you use a
mechanical pump, it must be well trapped to prevent oil back-streaming from the
mechanical pump to the ion pump.
3.
If an ion pump is used or has been at atmospheric pressure, it may be necessary to
bakeout the pump into the roughing pump to achieve the best pressure. This is done
by heating the ion pump (<300°C with magnets) for a period of several hours until
heat soaked.
To Start the Pump
Use the following procedure to start the pump. If your DIGITEL MPC is configured for
POWER-LOSS restart
, high voltage starts automatically when your turn on the DIGITEL.
1.
Turn on main power to the DIGITEL MPC. If in POWER-LOSS restart, go to Step
4. If in manual restart, go to Step 2.
2.
Press
9
to select
High Voltage Operate
.
2.1.
To turn supply 1 on (or off), press the top
Display Select
key to toggle to the
desired value.
