Contents page
Safety Precaution 3
Important safeguards 3
Looking after your
Micro/Micro Plus 3
Introduction 3
Before you begin 3
Micro/Micro Plus
system Overview 4
Micro Medical
Digital Volume
Transducer 5
Cleaning the Micro
Medical Digital
Volume Transducer 6
Micro/Micro Plus
exploded view 7
Disassembling the
Micro/Micro Plus for
Circuit Investigation 8
Reassembling the
Micro/Micro Plus 9
Circuit description 10
Technical Data 12
Technical support 13
Parts List 14
Circuit Diagram 15
Micro/Micro Plus
Service Manual
051-07 Iss. 1.0 September 1998
Micro/Micro Plus
Service Manual
Information in this document is subject to change without notice and does not represent a
commitment on the part of Micro Medical Limited. Only the parts supplied by Micro Medical
Limited should be used to complete the service operation described in this manual. If in any
way you feel unsure about the successful completion of the service operation you should
contact Micro Medical Limited or its appointed agent in your country or region and arrange the
despatch of the product to a Micro Medical Limited Service Centre.
Copyright 1998 by Micro Medical Limited All rights reserved
Drawing no. 051Version 1.0
September 1998
All other products are trademarks or registered trademarks of their respective owners.
2
Safety Precaution
The servicing of this device is intended to be carried out by a properly
trained and competent electronics engineer, or experienced in the
maintenance and servicing of medical devices. Read this manual
thoroughly before proceeding with the service. If in any doubt please
contact the service centre at Micro Medical Limited or their accredited
agent in your country or region.
Important Safeguards
o Read all of the instructions.
o Keep the instructions in a safe place for later use.
o Follow all warnings and instructions marked on the product.
o When replacement parts are required, be sure to use replacement parts
specified by Micro Medical that have the same characteristics as the
original parts. Unauthorised substitutions may result in fire, electric or
other hazards.
o Do not place on an unstable table.
o The product should be operated only from the type of power source
indicated on the label.
Looking after your Micro/Micro Plus Spirometer
o Avoid exposing the Micro/Micro Plus Spirometer to direct sunlight.
o Avoid operating the spirometer in dusty conditions or near to heating
appliances or radiators.
o Do not keep the spirometer in a damp place or expose it to extreme
temperatures.
o Do not direct the transducer holder towards a strong light source whilst
operating the spirometer.
Introduction
This service manual provides you with information to carry out the
servicing operation of the Micro/Micro Plus Spirometer. should the unit
become faulty It is a process, which is relatively straightforward but must
be carried out in a logical sequence. Our advice is to familiarise yourself
with the contents of this manual before attempting to carry out the
procedure of replacing the parts supplied in the service kit for the
Micro/Micro Plus Spirometer.
Before You Begin
Before you begin the servicing operation, please read the section on
Circuit description very carefully:
3
M
e
d
i
c
a
l
Micro/Micro Plus system overview.
The Micro Medical Micro/Micro Plus Spirometer consists of a hand held
microcomputer unit (2) incorporating a Micro Medical digital volume
transducer (1).
o
r
c
i
M
1. Micro Medical Digital Volume Transducer.
2. Micro microcomputer unit.
3. Lung Function Calculator.
4. PP3 Alkaline battery (BAT2).
4
Micro Medical Digital Volume Transducer
VOLUME PROPORTIONAL TO THE NUMBER OF PULSES
FLOW PROPORTIONAL TO THE PULSE FREQUENCY
The Micro Medical digital volume transducer consists of an acrylic tube
with a vane (3) positioned between a stator (1) and a cross bar (2). The low
inertia vane is attached to a stainless steel pivot (5) which is free to rotate on
two jewelled bearings (4) mounted at the centre of the stator plate and cross
bar. As air is passed through the transducer a vortex is created by the stator,
which causes the vane to rotate. The number of rotations is proportional to
the volume of air passed through the transducer and the frequency of rotation
is proportional to the flow rate. The transducer passes through the PCB,
which contains a light emitting diode (LED) and phototransistor. The LED
produces an infrared beam, which is interrupted by the vane twice per
revolution. This interruption is sensed by the phototransistor giving a square
wave output on the collector.
There is no routine maintenance required for the transducer other than
cleaning.
434
Flow
k/pulse
2
1
INFRA RED
EMITTER
5
INFRA RED
DETECTOR
Volume = k X No. of
5
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