Yokogawa GC8000 Process Gas Chromatograph - Manual (Page 50)

<1. Overview>
1-23
IM 11B08A01-01E
Protection system
Control unit
Oven unit 1
Oven unit 2
Oven unit 3
Stanchion*1
Flow
control
section
Warning plate
GC-HMI (touch panel) *2
Electronics
section
EPC box *3
LSV (liquid
sample valve) *1
Pressure
control
section *1
Isothermal
oven section
Data plate
*1 A stanchion is mounted on the self-standing type.
External sampling systems can be connected as needed.
*2 Depending on the specifi cations.
Figure 1.5 Structure and components of Type 3
1.10.2 Components and their Functions
(1) Protection System
The protection system is a fl ameproof enclosure and contains the protection circuit in the
pressurized enclosure. The Y-purging specifi cation (FM) does not use this system.
This device contains the power relay, pressure switch, timer, relay, illuminance sensor, and
override switch.
The device monitors the internal pressures of the pressurized enclosures (the electronic section
of the control unit and oven units 1 to 3, the large isothermal oven or the isothermal oven) while
the power is on, and if any of them indicates lower than 392 ± 20 Pa, the protection system will
automatically turn off the power.
This automatic power-off can be disabled by a function called “overriding.” To enable this
function, open the cover of the protection system and press the override switch while the
illuminance sensor is detecting light of 100 lx or more. When the illuminance becomes lower than
10 lx, the function becomes invalid, and the automatic power-off prevails. The override function
allows operators to open the door of the protection system while the power is on. However,
make sure the ambient atmosphere is not hazardous before opening the door for repairs or other
purposes.
Refer to Chapter 2 for details of checking the status display of the protection system and override
function.
* Guideline for illuminance and brightness
In an offi ce with fl uorescent lights: 400 to 500 lx
Under a street lamp: 50 to 100 lx
Candlelight (at a distance of 20 cm): 10 to 15 lx
Ordinance on Industrial Safety and Health, Article 604
For precision work: 300 lx or more
For ordinary work: 150 lx or more
For rough work: 70 lx or more
2nd Edition : May 11, 2012-00
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