STUDIA UNIVERSITATIS BABES-BOLYAI, PHYSICA, SPECIAL ISSUE, 2003
VACUUM SYSTEM PROTECTION AND AUTOMATION UNIT (VSPAU)
DESTINED TO MODERNIZE THE IZOTOPIC ANALYSYS MASS
SPECTROMEETER.
Nicolae Lupsa, Valentin Mirel, Stefan Popescu.
National institute for Research and Development of
Isotopic and MolecularTtechnologies , P.O.Box 700 ,
3400 Cluj-Napoca 5, Romania.
The high vacuum protection ensurance is necesarily so that the izotopic analys
mass specctrometer correctly work and require boths : the using of the high
performance vacuum pumps and the nonstop working of them. If tere no some
condition are assured during pumps running, they get out of order. For this reason
there is of capital importance the existence of a electronic unity destined to keep
working the pumps if there only the necessrily conditions are acomplished.
The isotopic analysis spectrometer vacuum system is made up by two distinct
subsystems : there is one wich assure the vacuum in the magnetic analisys chamber
and anoder wich assures the vacuum in the inlet subsystem.
The first subsystem is made up of preliminary vacuum pump , one turbomolecular
pump , air electrovalves and separation electrovalves, two gauges for preliminary
vacuum measure at the preliminary vacuum pump input, respectively at the
turbomolecular pump output and a high vacuum gauge for vacuum measure in the
chamber analyser.
The second subsystem is structured also by preliminary vacuum pump , one
spreading pump, air electrovalves and separation valves , two preliminary gauges
and a high vacuum gauge.
The V.S.P.A.U. consist of few parts like:
-the electronic circuitry for vacuum pomps and for electovalves action,
-the electronic relays for overload protection ,
-the vacuum measure circuitry coresponding to the vacuum goge,
-the logic circuitry wich assures pump working conditions check (protection
function) and the corect starting, respectivly stoping sequences (automation
function).
-assure the correct shut down of mass spectrometer in case of accidental net
voltage fall(power suplay interrupt protection) , and the automatic restarting when
the net voltage reappearence,
-for the VSPAU building we are designed and realized the electronic relays for
overload protection as well we are used the CMOS integrated circuits in local
protection logic of the the power components (pumps, electro valves ,heating
resistors).
By means of some dedicated microcontrollers there are achived starting
sequences and restarting protocols for the two vacuum systems .
NICOLAE LUPSA, VALENTIN MIREL, STEFAN POPESCU.
The block diagram for VSPAU is the following:
PG
Interface
ADC
P
G
MicroController
JT1
Interface
Vacuumcontrol
Module
JT2
Interface
PUMP
DRIVER
PTMM
TurboMolec.
Pump
EV
EVSM
S
JT
1
EVAM
Relays
Unit
EVA
JT2
PVPM
Fore
vacuum
pump
VACUUM SYSTEM PROTECTION AND AUTOMATION UNIT
The major fuctions of the unit are accomplished by the following modules:
1.Vacuum control module.
a)
It manages the logical signals from the vacuum guages and made the
comand signals in corelation with the other sistem components.
b) Memorise all the abnormal events.
2.
PVPM
This module check and assure the forre vacuum pump whith protection at
short circuits and overoad.
3.
EVSM
Manage the separation valve during the start, stop and restart after failure
proces of the mass spectrometer.
4.
EVAM
This module drive and check the air electro- valve and memorise the failure
events.
5.
PTMM
Make the conection the micro-controler module and the turbo-molecular unit
giving the Start- Stop commands and checking the signals from it.
All of this modules are interconected with the microcontroler unit by a bus
system.
The micro-controler unit manage:
-Start sequence comands
-Stop sequence comands
-Acquire the signals from the vacuum guages
-Liniarise the transfer function of the vacuum guages
- Digitaly display for the vacuum sistem parametrs.