9
The ceiling alarm set point provided for Ex
Chek detectors are set conservatively at the
factory to maximize worker safety.
The procedures for adjusting alarm set
points or restoring the factory default
settings are given in section 4.1.
1.6.2 Low battery alarms
The rechargeable version of the EX Chek is
equipped with a sealed rechargeable NiMH
(nickel metal hydride) battery that is
designed to provide up to 6 hours of
continuous use.
When it is time to replace the batteries a "
B
"
will appear in the lower left hand corner of
the display screen, and the audible alarm
will “beep” once per minute until the battery
is replaced. Once the batteries are no
longer able to provide adequate power to
the instrument an audible chirping alarm will
sound for 20 seconds and the display will
toggle:
D E A D
↑↓
B A T T
After 20 seconds, the instrument will shut
itself off. The battery should be recharged
as soon as possible after any low battery
message is displayed.
Section 2.3.1 below covers battery
charging procedures.
1.7
Special microprocessor
features
Several automatic programs prevent
tampering and misuse of the Ex Chek by
unauthorized persons. Each time the
detector is turned on, an electronic self-test
is performed that assures the user of proper
performance. The sensor, LED alarm light,
and audible alarm are automatically
evaluated, and the battery is monitored
continuously for proper voltage.
The Ex Chek offers the following additional
options that allow the user to customize the
instrument for his/her own use.:
•
security
beep
•
latching
alarms
•
calibration gas concentration settings
•
alarm
settings
Chapter 5 describes how to use these
advanced technical features and setup
choices in greater detail.
1.8
Classification for intrinsic
safety
The Ex Chek is Classified by Underwriters
Laboratories, Inc., as to Intrinsic Safety for
use in Hazardous Locations Class I,
Division I, Groups A, B, C, & D. and Class II
Groups E, F, & G, the Canadian Standards
Association for use in Class l, Groups A, B,
C, and D, and the European Community
(DEMKO Certificate number
99E.9933271X), EEx ia IIC T4 for
instruments powered using DEMKO
approved alkaline batteries.
Classification for intrinsic safety is based
on tests conducted in explosive gas / air
(21 % Oxygen) mixtures only.
1.9
Options
1.9.1 Vibrator Alarm
An optional internally mounted vibrator type
alarm is available for use in high noise or
other environments requiring additional
warnings. The vibrator alarm option must
be specified at the time the instrument is
purchased.
1.9.2 Remote sample draw kit
An optional hand aspirated (squeeze bulb)
sample draw kit is available for use in
situations where the sample must be
obtained from locations that are remote from
the instrument. The sample draw kit
consists of a sample draw adapter, squeeze
