EIALZERS
-Connecting the mains power cable first, make the cable
connections. 3.8.1 Test sockets
-Turn the unit(s) on again <sync> Signal for triggering arecording instrument
<elm> Output signal from the prefiltered electrometer
preamplifier
3.4 Installing the OMS in a19" rack <mon> Measured value from the selected measure-
The QMS 421 can be installed in aD1N 41 494 19" ment channel or from the sequential measure-
rack, ment signal output
<scan> Analog signal that is afunction of the mass
DANGER: If the unit is to be installed in arack' number. Used for recording spectra on astrip
it must not lower the protection level chart recorder.
of the rack (protection against foreign
objects and water) e.g.
DIN VDE 0113 regulations for switch 3.8.2 <ctrl> multipoint connector
cabinets when in place. The signals relayed via this connector are:
CAUTION: The temperature inside the rack must 'ELM OUT'
not exceed +40 °C. Take care that
air can freely circulate through the Electrometer preamplifier output signal. This is the
built-in fans. same signal that is present at the <elm> test socket.
'EXT IN'
When <detect> «TYPE» :«EXTERN» is entered, an
3.5 Setting up the OMS as abench unit external detector can be connected through here and
When the protective cover available as an option (see its input signal processed,
section 10.1) is mounted, the QMS 421 can be set up as 'EXT PROT'
abench unit, it has folding legs that allow it to be set at Extemal protection control input for the filament and
aslight angle for better viewing and easier access to the SEM supply, Its function is determined by the
front panet <ion src> «CTRL» «SEM+ FIL» sequence entered.
/CAUTION: When setting the QMS 421 up as a'INT START'
bench unit, be sure that air circulation
in through the cooling slots on the When <integ> «TRIG» :«EXTERN» is entered, the in-
side of the unit and out through the tegrator is started by the trigger signal coming via this
back of the unit is unhindered, pin.
'RUN IN'
Depending on the parameter setting for <cycle>
3Periptiery cornpOnents «TRIG», the measurement cycle is started by the trig-
ger signal coming via this pin,
install periphery components such as the analyzer, elec-
trometer preamplifier, etc. according to the separate ope Using an appropriate matching connector (refer to sec-
rating instructions for the components (see appendix J). tion 10.1), make aconnection cable suited to your appii-
cation. Refer to section 7,2.2.9 for the pin assignments.
3.7 Cabling 3.8.3 <AO> connector
if you do not want to use the AB 021 connection box
Cable the system as required for your particular OMG available as an accessory, you can fabricate you own
system version. Refer to Appendix Bor Cfor the correct connection cable using amatching multipoint connector
cabling for your version' (refer to section 10.1). Refer to section 7.2.2.10 for pin
assignments.
INOTE: Be sure the <polarity> switch on the
OME 125 is set to <+>. 3.8.4 <RS 232> and <LAN> connectors
For the pin assignment for the above connectors, please
refer to the separate opeating instructions for the inter-
3.8 Special applications faces (61.
The test sockets and <ctrl> and <AO> connectors are
of particular interest for certain applications. See section
6.3.
10 Installation QMs421eg.opm