impact BM350 User manual

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User Guide
User Guide
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Methylene Chloride Monitor
BM350
Impact Test Equipment Ltd
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Impact Test Equipment Ltd.
Building 21 Stevenston Ind. Est.
Stevenston
Ayrshire
KA20 3LR
T: 01294 602626
F: 01294 461168
E: [e-mail]
Test Equipment
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Contents
Product description and safety features
Installation instructions
Power connection
Relay connection and mounting location
General information and operation
Additional Information re sensor performance
Maintenance and Flying Lead Sensor
Technical specification
Page
2
3
4
5
6
7
8
9

2
General Information
The BM350 gas monitor offers a robust, easy to use, cost effective approach to providing a gas
monitoring system where safety matters.
The monitor’s fibreglass housing is weather and corrosion resistant. It is suitable for installation
where general equipment is in use. The housing door is hinged on the left side and is secured
on the right with one latch. The display screen and status lights are visible through the
transparent hinged cover. Optional mounting feet can be fixed to the back panel for vertical
mounting.
The alarm buzzer is located at the bottom of the unit and is on the left side of the power input.
The gas sensor element is located on the bottom of the unit on the far left hand side. (or on a
3M or 5M trailing cable)
A large LCD display indicates vapour level.
The concentration of Vapour is displayed in either parts per million (ppm) or milligram’s per
cubic meter (mg/m3 ) depending on your specific requirements.
The unit has an alarm, both audible and visual, and when a predetermined level of s is reached
the alarm is activated, this alarm level is set at manufacture to customers requirements
The monitor incorporates three fuses one domestic 3 amp plug head fuse, and one internal
circuit board mounted 1Atime delay fuse, and one 2A fuse to protect the alarm relay.
If required an external alarm or device can be connected to the unit to provide other warnings of
alarm level see installation instructions for more detail.
The monitor is very easy to operate and requires no specialist knowledge or training.
Automatic self-test
The monitor incorporates a self testing feature, to quickly inform the user that monitoring is
compromised, all foreseeable modes of failure have been taken in to account, in the unlikely
event of a system failure the user will be alerted by the sensor malfunction light.
Operating requirements
The unit requires connection to a permanent electrical supply, see specification for your model
on page.
Consideration should be given to the power connection, if possible try not to use switched
sockets or extension leads as these can easily be turned off leaving the monitor without power.
The monitor is designed for indoor use only and should not be exposed to very high levels of
condensing moisture.
Technology
The monitor uses the latest printed circuit technology, component parts have been selected to
provide a high level of reliability combined with low drift over time.
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3
Equipment suitability
This monitor is designed primarily for use in blacktop Laboratories, to monitor the process of
bitumen binder recovery from road materials, and alert the user to flask bung failures, leaks in
the Methylene Chloride supply system, or fume extraction failures, it is also suitable for use in
still recovery rooms as a leak detector.
Because the unit does not have any data logging capacity or time weighted average
functionality, is not suitable for monitoring personal exposure to dichloromethane vapour beyond
alerting the user to a preset alarm level, in most cases 100 parts per million.
Installation instructions
Please read the following information carefully before installing the unit. The information
contained in this manual, and the specifications are correct as of the date of publication.
This operation manual is designed to give users precise information on how to install and use
the monitor. Although every effort is made to ensure accuracy, this manual may contain
technical unintentional technical inaccuracies.
On behalf of its clients, Impact reserve the right to modify the technical characteristics of its
equipment without notice to improve product performance.
Safety Warnings
Installation and any electrical connections should be performed by a qualified professional,
failure to observe these rules may result in serious injury.
Important information
The modification of any component or the use of any third party components will automatically
void any and all guarantees.
Limitation of liability
Neither Impact nor any associated organisation shall be held responsible under any
circumstances for any damage whatsoever including without limitations, damages for loss of
manufacturing production, interruption to that production, the loss of company information,
instrument failure, personal injury, loss of materials, loss of time, loss of money or for any
indirect or consecutive consequence of loss occurring during the use of this product or the
inability to use this product.

4
Unpacking
Carefully unpack the monitor; each monitor comes with operating instructions, and calibration
certificate
At this point check the front panel of your monitor, the target gas and alarm level will be clearly
shown, if either of them are incorrect contact your supplier.
Power connection
The monitor will operate on voltages from 110-250 VAC/ 50 Hz
Connect the monitor to a permanent power supply, preferably none switched, the unit is supplied
with a mains lead terminated in a molded mains plug, therefore connection is simply a mater of
plugging in to a socket outlet.
If you require to connect your monitor to an existing circuit, this might be necessary where no
socket outlet is present, firstly ensure the mains lead is not connected, isolate the plug so it
cannot be connected accidentally, loosen the two screws holding the lower cover in place,
remove the cover, the mains lead connections can be clearly seen on the right hand side of the
circuit board, (see fig 1) use a terminal screwdriver to loosen the three screws, then loosen the
cable clamp removing the lead through the bottom of the case, give careful consideration to
disposal of the mains lead, if plugged in it could be dangerous.
Connection of your power lead (hard wire) is the reverse procedure ensures the cable you use is
at least 7 mm in overall diameter; smaller cables cannot be clamped properly.
Cable removal and replacement must be done by competent personnel
Fig 1Picture of monitor with cover removed
The Relay connections on the left

5
Installation instructions continued
Relay connection for external alarm
One solid state relay is accessible for connection via a terminal strip located beneath the units
lower cover, this terminal strip is clearly visible in fig 1 top of page, if you need to make a
connection simply knock out the cable entry cut out beneath the relay terminal strip, and fit a 20
mm cable gland the relay contacts carry no voltage and are isolated.
SRC Relay specification
The relay is an SCR not ideally suited for switching inductive loads; try to use resistive loads
where possible, such as lights, buzzers, sounders etc. Only AC loads can be switched by the
relay, the voltage is 12 VAC to 240 VAC, Max current is 2A, Minimum AC load is 60 Ma
One normally open connection is available; the relay is active when an alarm condition is
present.
Relay connection on PCB
1= 1 Com
1= 1 out NO
Powering for the first time
After connecting the power, the unit requires up to three minutes to stabilize,
During this time the monitor alarm circuit is muted and the displayed reading is held low, this is a
normal and necessary part of installation, after a short time the reading should settle down close
to zero, any reading from -0.05 to + 0.05 is acceptable.
Note: It may take up to 24 hours for the reading to stabilize fully, if the unit is
commissioned in an atmosphere containing the target or other gas of the same group a zero
reading will not be possible, it is therefore advisable to first connect the unit in a place with clean
air other than the units intended monitoring location. After a low reading is achieved move the
monitor to its intended location.
Mounting location
Before mounting the monitor, experiment with several different locations, this is to avoid
nuisance alarming, bear in mind a lot of gasses are heavy and tend to concentrate at lower
levels, if for example two chemicals are present within the monitoring area, site the monitor
well away from the second chemical, if the room is not adequately ventilated a below alarm
level will not be possible.
Avoid mounting the monitor above a source of heat, radiator heating vent etc, fast moving air is
not representative of the areas average gas value.

6
Wall mounting
Never mount the unit on a wet wall, the monitor is intended for indoor use only
disconnect the power before wall mounting the monitor
The monitor has a molded cut-out on the reverse side, this is used for single point mounting on a
screw protruding from the wall, simply hook the monitor over the screw making sure it’s latched
on properly, if extra stability is required two further through hole mountings are available behind
the lower cover.
General information
Large Liquid crystal display: This indicates detected gas concentration.
Observe display for gas level detected.
Alarm LED: This indicates a level above the pre-set alarm level has been reached.
Alarm sounder: This activates when the alarm state is reached giving a high pitched
continuous tone.
Sensor malfunction LED: This alerts the user that a variation away from normal parameters
has been detected: the monitor may continue to function if this occurs please contact your
supplier for service.
Operation
Following an initial warmup period of 3 minutes, providing the sensor malfunction warning is not
indicating a fault, the instrument is ready for use.
Other than periodical observation of the display, no other action is necessary by the user, it is
important to remember that no alarm is possible in the event of a power failure.
Under no circumstances should the monitor be used if the Sensor malfunction light is activated,
in the case of a sensor malfunction discontinue use of the instrument and contact your supplier.

7
Additional Information regarding sensor performance
Avoid exposing the sensor to adhesives containing silicone. Silicone can damage the sensitivity
of the sensor element
Avoid highly corrosive environments. High density exposure to corrosive gases such as
hydrogen Sulphide, Sulphur oxide, chlorine, hydrogen chloride, etc. for extended periods may
cause internal damage to the sensor element
Avoid contamination by alkaline metals. Sensor characteristics may be significantly changed if
the sensor is contaminated by alkaline metals, especially salt-water spray.
Sensor performance may be affected if exposed to a high density of reactive gases for a long
period of time, regardless of the powering condition
If water freezes on the sensing element surface, the sensing material may crack, which will
irreversibly affect sensor characteristics.
If water condenses on the sensor element surface and remains for an extended period, sensor
characteristics may temporarily drift. Light condensation under normal conditions of indoor
usage would not pose a significant problem for sensor performance.
Regardless of its powering condition, if the sensor is exposed in extreme conditions such as very
high humidity, high temperatures, or high contamination levels of organic vapours or other gases
for a long period of time, sensor performance may be impaired.
MOS-type gas sensors cannot properly operate in a zero or low oxygen content atmosphere.
They require the presence of normal ambient oxygen in their operating environment to function
properly.
Sensor characteristics may be changed due to soaking or splashing the sensor with water.
Avoid mechanical shock. Breakage of lead wires may occur if the sensor is subjected to a strong
shock.
Under no circumstances should the sensor be disassembled, nor should the sensor can and/or
cap be deformed. Such action would void the sensor warranty and would cause irreversible
change in characteristics.
When stored without powering for a long period, the sensor may show a temporary drift in its
response depending on the environment in which it was stored. Such drift is reversible.
Powering the sensor will offset this drift and stabilize the sensor. The longer the unpowered
storage period, the longer the conditioning period required to stabilize the sensor before usage.
Every installation is different, it may be the case that you have to relocate the monitor, and
improve ventilation to prevent intermittent nuisance alarming.

8
Maintenance
We strongly recommend that the user periodically inspects the instrument to make sure the fault
indicator is not active.
Servicing frequency
Impact recommends regulator testing of fixed gas installations. This type of test consists of
injecting a standard gas of sufficient concentration in to the sensor in order to trigger the alarm.
Frequency of testing depends on the application the detector is being used for, if a detector does
not react upon contact with gas, it must be repaired and or calibrated, the frequency of
calibration will depend on tests(humidity, temperature, dust etc) calibration should occur at least
once a year.
The site manager is responsible for implementing the safety procedures on his site. Impact is
not responsible for implementing safety procedures.
Sensor location (Flying lead version)
Dichloromethane vapor tends to be heavier than air and without the influence of air currents and
negative pressure, will concentrate at lower levels, please consider this when fitting as a spill
alarm.
In general the sensor is mounted at around operator working height externally to the fume
cupboard; try to avoid mounting the sensor too close to the fan extraction as this may unduly
affect the sensor.
Never expose the sensor to Dichloromethane directly, as this will immediately destroy the
sensor.
.

9
BM350 Technical Information
Technical Characteristics
Supplier Impact Test Equipment
Miscellaneous
GSS Semiconductor
Code BM350
Temperature compensating
Function
Solvent Detection
Surge Protected
Capacity
1 channel
Housing: ABS Sealed to IP 67
Measurement
Continuous diffusion
Warranty: 1 year
Range
0-199ppm / 0- 2000mg/m3
Dimensions
210 x 185 x 110 mm
Accuracy
+- 10 % Cal level
Visual alarm
Red alarm led
Weight
0.4kg
Audio alarm
Integrated sounder
Response
time
30 Seconds (Typical @ 100
ppm)
Malfunction
alarm
Yellow malfunction led
EMC
BS EN 61000-6-3:2007+A1:2011
BS EN IEC 61000-6-1:2019
Supply
voltage
100-250v AC 50HZ
Detection
Principle
Chemo absorption
Operating
Temperature
-10°c to + 85°c
Operating
Humidity
0-95% non condensing
Relay
outputs
SCR 250 v AC
2A Max
Current
consumption
0.03 A Typical