Switching On; Category 2 System; Category 3 System - Emerson ROSEMOUNT MLT 2 Upgrade Manual

MLT 2 / BINOS
3.2

Switching On

During the prepurge phase (Category 2 systems: always before analyzer
is connected to power; Category 3 systems: optional) all non-intrinsically
safe inputs and outputs connected to external equipment MUST be shut
off too!
This ensures that no hazardous voltages are present within the analyzer
enclosure when not pressurized.
3.2.1

Category 2 System

The analyzer system is switched on by sup-
plying power and protective gas.
The pre-purge phase is initiated to flush out
possibly potential internal atmosphere, while
the analyzer electronics remains unpowered
(an indicator is the de-activated display).
The control unit´s display gives information
about the current status.
Once the pre-purge phase has ended, the
control unit starts into the leakage com-
pensation mode and supplies power to the
analyzer.
The system now is operable.
3-2

100 F
3.2
EXPLOSION HAZARD
Switching On
3.2.2

Category 3 System

Power supply for control unit and analyzer
need to be provided separately:
First switch on the control unit by supplying
power and protective gas.
Dependent on the setup a pre-purge phase
may start to flush out possibly potential inter-
nal atmosphere, while the analyzer electro-
nics remains unpowered (an indicator is the
de-activated display). During this phase the
analyzer must be switched off!
The control unit´s display gives information
about the current status.
Once the pre-purge phase has ended (or
- if such is not required - immediately after
switching on the control unit), the control unit
starts into the leakage compensation mode
and the analyzer can be switched on, too.
The system is now operable.
Emerson Process Management GmbH & Co. OHG
ATEX Instruction Manual
ETC01035
02/2008