Spiro USB Service Manual - Frank`s Hospital Workshop
Contents
1. Title n i p Spiro USB Circuit diagram memory Size Number Revision 075 02 1 0 A3 Date 12 Feb 2004 Sheet of File G Archive Temp 075 Drawn By Arthur Sadler 6 7 82. microprocessor data bus and one address line AO The 512k x 8 static RAM U8 is located on the underside of the PCB and communicates with the processor on the 19 bit address bus and 8 bit data bus The speaker J1 is directly connected to ports on pins 91 and 92 that are toggled at 1 KHz to generate the sound Drawing No 075 00 Revision No 1 4 Page 1 OF 3 Designation Part No U1 BU4S11 Individual CMOS Schmitt NAND gate U2 4LC00 OT 128 bit serial EEPROM U3 HD64F2318VTE25 Hitachi microcontroller U4 BU4S584 Individual CMOS Schmitt inverter U5 BU4S584 Individual CMOS Schmitt inverter U6 SL811HST USB interface U7 MAX6349TL 3V3 regulator with integrated RESET U8 K6X4008T1F VF70 512k X 8 bit CMOS static RAM U9 DS18S20 Digital thermometer R1 DTD113EK NPN digital transistor R1 100K resistor 1 R2 100K resistor 1 R3 180 Ohm resistor 1 R4 10K resistor 1 R5 10K resistor 1 R6 1K resistor 1 R7 4 7K resistor 1 R8 4 7K resistor 1 R9 22 Ohm resistor 1 R10 22 Ohm resistor 1 R11 1 5K resistor 1 R12 120 Ohm resistor 196 R13 100K resistor 196 C1 33pF ceramic capacitor C2 33pF ceramic capacitor C3 100nF ceramic capacitor C4 100nF ceramic capacitor C5 100nF ceramic capacitor C6 100nF ceramic capacitor C7 1nF ceramic capacitor C8 1nF ceramic capacitor C9 100nF ceramic capacitor C10 100nF ceramic capacitor C11 4 7uF ceramic capacitor C12 100nF ceramic capacitor C13 1uF ceramic capacitor L1 LQW18ANR22G00D 220nH inductor 1 12
3. EEPROM is carried out using a two wire serial connection to pins 54 and 55 of the microprocessor If the device is ever replaced the unit will have to undergo factory recalibration Ambient temperature is monitored by a solid state temperature sensor U9 It communicates with the microprocessor via a one wire serial interface on pin 90 The ambient temperature reading is used for adjusting inspiratory volume at ambient temperature to volume at body temperature The supply to the two series LED s mounted inside the transducer housing is provided through TR1 which is switched on by pin 4 of the microprocessor during a spirometry manoeuvre Inside the transducer housing the two phototransistors used to detect the interrupted infra red beam are in open collector configuration The pull up resistor for the two phototransistors is provided by R7 and R8 Pulses from the phototransistor TR2 are applied to the pulse timing input of the processor pin 5 after being squared up by the action of the Schmitt inverter U4 Pulses from the second phototransistor TR3 after conditionings U5 are applied to pin 6 of the microprocessor and are used to determine the direction of flow The pulse count is used to determine the volume passed through the transducer since the start of the test and the pulse period is used to determine the flow at each volume increment The microprocessor communicates with the host PC via a USB interface U6 U6 is connected to the
4. MHz crystal LED L934MBC Blue LED LED2 SEP8705 Infra red LED LEDS SEP8705 Infra red LED R2 SDP8405 Infra red photo transistor R3 SDP8405 Infra red photo transistor vec sv vec A UT L mw our 2 5 10UF 6V3 GNDISET C10 co C6 C5 o le PROGRAMMING PORT 3 Jan mst SRESET O luF ni OluF OluF Oou gt cu vec vec MAX6349SL_ BUASII DS18S20 Temperature Sensor 5V 12 120R USB CON 1 2 BU4S584 gm ag VK E e ED3 TEMTI288C Note U6 SL8IIHST LED2 LED3 TR2 and TR3 are external components iy 2 R6 IKO BUZZERII ED2 TEMT1288C R3 v IDETO Y RI TDII3EK vec vec RS 10K 4 10K vec uz SCL VCC vss c3 SpA NG Ld 100nF 24LCO OT HD64F2318VTE25 Title USB SPIROMETER Number Revision 075 01 1 2 12 Feb 2004 Sheet of GAArchiveVTempW7 01 sch Drawn By Arthur Sadler 2 3 6 7 8 6 Us K6X4008T1F VB70 vec ss a OR DS e o 55 a Eis 4 A4 Di R 5 e Bel 20 v AS Ds O DE Ai p7 AS AO AIO AU AD AB Ald AIS Ain AIT AIS E WE CSI 512Kx 8 DI
5. Spiro USB Service Manual 075 12 Revision 1 0 February 2004 Micro Medical Limited P O Box 6 Rochester Kent MEI 2AZ Spiro USB System Overview Fig 1 The Spiro USB is a PC connected spirometer dedicated to work with SPIDA 5 spirometry software It consists of a removable digital volume transducer 1 and a housing 2 containing a microprocessor control circuit and USB driver When testing a subject the transducer is inserted into the housing which is plugged into a USB socket of a PC The digital volume transducer is used to measure the subjects expired flow and volume in accordance with the operating manual fe X b 2 8 KS E Pd AN O M qu Transducer Fig 2 The Micro Medical digital volume transducer consists of an acrylic tube with a vane positioned between two swirl plates The low inertia vane is attached to a stainless steel pivot which is free to rotate on two jewelled bearings mounted at the centre of the swirl plates As air is passed through the transducer a vortex is created by the swirl plates which causes the vane to rotate in a direction dependant upon the direction of air flow 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 housing consists of a
6. main body which contains a pair of light emitting diodes LED s and phototransistors The transducer is fixed to the mouthpiece holder which pushes into the main body and is captured by an O ring seal The LED s produce infra red beams which are interrupted by the vane twice per revolution This interruption is sensed by the phototransistors The output from the collector of each phototransistor will be a square wave with a phase difference between the two of or 90 degrees depending upon the direction of flow There is no routine maintenance required for the transducer other than cleaning according to the instructions in the operating manual Micro Medical Digital Volume Transducer Rotating Infrared Swirl Jewelled vane emitter plate bearing OOOGGO ke HASS ri Infra red detector pones k X No of pulses Volume proportional to the number of pulses Flow proportional to the puse frequency n pi m Flow k pulse period Disassembly Fig 3 1 Carefully remove both Spiro USB labels from the transducer housing 2 Remove the screw under each label 3 Pull apart the two halves of the housing as shown below Reassembly Fig 4 Please note Do not use excessive force when reassembling 1 Ensure the PCB is aligned correctly as shown in Fig 4 2 Pull the cable gland through the hole in housing A already on the cable and locate
7. the centre moulding into the housing 3 Line up the channel on the centre moulding with the screw hole of housing A 4 When refitting housing B locate the moulded bracket with the nut between the end of the channel and housing A and carefully pivot housing B around until the two housings meet ensuring the blue LED fits into it s hole 5 Replace the screws 6 Carefully reposition the Spiro USB labels The PCB LED S and phototransistors will be accessible as shown below Fig 4 Channel Centre moulding VA Microprocessor control circuit see drawing 075 01 and 075 02 The microprocessor control circuit monitors the transducer pulses carries out the spirometry routines and communicates with the PC via a USB driver under the control of it s internal program Power for the processor circuit is derived from the 5 volt USB power line The power line is filtered by C12 L1 and C13 The filtered 5 volt is regulated down to 3 3 volts by the linear regulator U7 U7 also provides a reset signal for the microprocessor The microprocessor U3 is a Hitachi HD64F2318 16 bit microprocessor with 256K of flash memory and 8K of Ram The system clock is supplied by 12MHz crystal X1 There is also 512 Kbytes of external RAM U8 used for storing pulses during a spirometry manoeuvre The internal flash memory is used to store the microprocessor firmware Calibration data and system data is stored in an EEPROM U2 Communication to the
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