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REMOTE INTELLIGENT SENSOR - AREA MONITOR
Instruction 2772-0803 Page 2-3
2.5.2.3 ‘Worst Case’ Current.
Low Flow RIS. A practical ‘worst case’ current
of 500 mA may be considered reasonable under most
situations. Where long-term power disruptions (more
than 2 hours) are likely, it may be prudent to
assume 550 - 700 mA ‘worst case’.
High Flow RIS. A practical ‘worst case’ current
of 600 mA is reasonable in most circumstances; in
severe conditions 650 - 800 mA may be prudent.
2.5.2.4 Alarm Module. With both horn and flasher
alarms operating and a well charged battery, the
input current is typically 100 mA.
After a power interruption, with the battery
discharged, and the alarm in the ‘standby’ state
(both horn and flasher off), a practical ‘worst case’
current of 200 mA is considered reasonable.
2.5.2.5 Summary: 'Worst Case' Input Currents.
Model ‘Practical’ ‘Extreme’
Worst Case Worst Case
Low Flow 500 mA 700 mA
High Flow 600 mA 800 mA
Alarm Module 200 mA 250 mA
2.6. SAMPLE LINES
2.6.1 GENERAL. The RIS is designed, tested and
calibrated to give accurate measurement of the
target gas when used as supplied and as directed in
this manual. This particularly includes using the
short input tube fitted to the RIS. The input tube,
material, diameter and length have been carefully
selected so that no attenuation of the sample occurs
as it is drawn into the monitor for measurement.
NOTE: GMD Strongly Recommends
only the original input tube be used. Refer
to Section 5.3 (Recommended Spares).
2.6.2 LESS REACTIVE GASES. They are less
liable to be ‘lost’ in sample lines but many factors
are involved. These include temperature, humidity,
and sample velocity.
It may be possible with some of these gases, and
under specific circumstances, to use somewhat
extended sample lines. It is not possible to give more
specific guidance on this subject than the following
comments:
The less reactive gases referred to above include,
PHOSGENE, HYDRIDES and CHLORINE. In
some circumstances, it may be possible to use an
input tube of
up to a maximum of about 36 inches
(0.91 meters) in length. The material MUST be
black FEP Teflon fitted to the RIS as supplied.
RIS TYPE Acceptable Combinations
Standard 4321
and + or+or+or+
Alarm Module 0248
High Flow 3 2 1
and + or + or +
Alarm Module 0 4 7
Alarm Module 10
NOTE: In large applications physical
layout and distance between RIS’s and
Alarms may make it more convenient to
use some small local power supplies.
2.5.2 POWER REQUIREMENTS, RIS &
ALARM MODULE. Typical current consumption
under a range of operating conditions are:
2.5.2.1 Standard RIS Models. All Standard
systems (See Table #1) have Flow Rates of 200 cc/
min. or less. This list may be incomplete because of
new models introduced after publication.
The input current taken by an RIS depends
upon the following factors. The battery charge
state, its condition and age, the operating point in
the cycle, pump current and the options fitted.
Typical input current, under several conditions:
Normal conditions, well charged battery.
Conditions and Comment mA
System running, no pump (as measured 60-
in the TEST Mode, mA test) 90
System running, pump on (measure at J1 150-
terminal #2, or as shown on print header) 200
Battery discharged, power just restored.
Conditions and Comment mA
System running, pump on. (Current 500-
shown is short term peak and would 700
only occur after a prolonged power
disruption. An old battery tends to take
a lower charging current)
2.5.2.2 High Flow RIS Models. All of these
systems (Table #1) have a the larger pump taking
an additional current of, typically, 100 mA. All
other factors are as detailed under Section 2.5.2.1.