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GymnaUniphy Phyaction Service information

SERVICE INFORMATION PHYACTION GUIDANCE-E/GUIDANCE-C
Version 0.5 May 2002
Phyaction Guidance E/C – service manual version 0.5 Page 1
1. TABLE OF CONTENTS

1. TABLE OF CONTENTS ................................................................................................ 2

2.
2.1 Introduction. ............................................................................................................................5
2.2 Information. .............................................................................................................................5
2.3 Safety aspects. .........................................................................................................................5
2.3.1 Electrical safety.............................................................................................................5
2.3.2 Explosion safety............................................................................................................6
2.3.3 Operational safety. ........................................................................................................6
2.3.4 Use of the appliance......................................................................................................6
2.3.5 Product documentation. ................................................................................................6
2.3.6 Radio interference suppression and electromagnetic compatibility..............................6
2.3.7 Medical device directive (MDD) ..................................................................................6
2.4 Installation. ..............................................................................................................................7
2.4.1 Incoming inspection......................................................................................................7
2.4.2 Mains voltage................................................................................................................7
2.4.3 Functional test...............................................................................................................7
2.4.4 Selecting the operating language. .................................................................................7
2.4.5 Location and transportation. .........................................................................................7
3.
3.1.1 Output connectors and control keys ( drawing unit on last page of service manual). ..8
3.2 Display indication overview....................................................................................................9
3.3 Technical specifications.........................................................................................................10
3.4 Different symbols. .................................................................................................................10
3.4.1 Symbols on the front of the Guidance E/C .................................................................10
3.4.2 Symbols on the right side of the Guidance E/C..........................................................11
3.4.3 Symbols on the left side of the Guidance E/C ............................................................11
3.4.4 Symbols on the back of the Guidance E/C .................................................................11
3.4.5 General symbols .........................................................................................................11
3.4.6 Symbols current groups ..............................................................................................11
3.4.7 Symbols currents ........................................................................................................12
3.4.8 Parameter symbols......................................................................................................12
4. UNIT SELF TEST. ....................................................................................................... 13
5.
5.1 Main PCB (ELUS004-L100).................................................................................................14
5.1.1 Power supply. .............................................................................................................14
5.1.2 Micro-controller Circuits. ...........................................................................................15
5.1.3 Safety control circuits. ................................................................................................16
5.1.4 Signal processing circuits. ..........................................................................................17
5.1.5 Stimulation circuits.....................................................................................................17
5.1.6 Current measuring circuits..........................................................................................19
5.2 Output circuits. ......................................................................................................................19
5.3 Console circuits. ....................................................................................................................20
5.4 Ultrasound circuits (only for Guidance C) ............................................................................21
5.4.1 PLL .............................................................................................................................21
5.4.2 Voltage controller. ......................................................................................................21
5.4.3 Power stage.................................................................................................................21
5.4.4 Impedance matching ...................................................................................................22
5.5 RS 232 communication..........................................................................................................22
Phyaction Guidance E/C – service manual version 0.5 Page 2
5.6 Vacuum unit. .........................................................................................................................22
5.6.1 General information....................................................................................................22
5.6.2 Vacuum circuits. .........................................................................................................23
6. Ultrasound heads (only Guidance C) ............................................................................ 24
7.
7.1 Safety inspection....................................................................................................................25
7.2 Inspection interval. ................................................................................................................25
7.3 Inspection results. ..................................................................................................................25
7.4 Different current wave forms for checkup.............................................................................25
7.4.2 General Functional Inspection ....................................................................................27
7.4.3 Functional Inspection Electrotherapy .........................................................................27
7.4.4 Electrical Safety Test According to VDE 0751..........................................................28
7.4.5 Result of safety inspection..........................................................................................28
8. SYSTEM SETTINGS MENU. ..................................................................................... 29
8.1 Contrast settings. ...................................................................................................................29
8.2 Language. ..............................................................................................................................29
8.3 Sound settings........................................................................................................................29
8.4 Change pre settings................................................................................................................30
8.5 Stand by time. ........................................................................................................................30
8.6 Plate electrode test. ................................................................................................................30
8.7 Cable test. ..............................................................................................................................32
8.7.1 Vacuum cable test.......................................................................................................32
8.7.2 Electrode cable test. ....................................................................................................33
8.8 System information................................................................................................................34
8.9 First screen.............................................................................................................................35
8.10 Copy parameters. ...............................................................................................................35
9.
9.1 Counter working hours. .........................................................................................................36
9.2 Error history...........................................................................................................................37
9.3 Reset working hours. .............................................................................................................37
9.4 Reset all user settings.............................................................................................................38
9.5 Total reset settings. ................................................................................................................38
9.6 Special service menu. ............................................................................................................38
10. UPGRADING SYSTEM SOFTWARE ........................................................................ 40
10.1 General information. ..........................................................................................................40
10.2 Which tools are required ? .................................................................................................40
10.3 Downloading the software. ................................................................................................40
10.4 Troubleshooting. ................................................................................................................41
11. HARDWARE LABELS................................................................................................ 42
11.1 Upgrading the hardware code. ...........................................................................................42
TROUBLE SHOOTING ............................................................................................... 43
12.
12.1 General information. ..........................................................................................................43
12.2 Interpreting error codes......................................................................................................44
12.3 List of error codes. .............................................................................................................45
12.3.1 Drivers (0XX).............................................................................................................45
12.3.2 Operating system (1xx)...............................................................................................46
12.3.3 Electrotherapy task (2xx)............................................................................................46
12.3.4 Ultrasound task (3xx) NOT FOR GUIDANCE E ......................................................47
12.3.5 Laser task (4xx) NOT FOR GUIDANCE E/C............................................................47
12.3.6 User interface task (5xx).............................................................................................47
12.3.7 System task (6xx) .......................................................................................................48
12.3.8 Processor test (1000)...................................................................................................49
Trouble shooting vacuum circuits................................................................................. 51
13.
Phyaction Guidance E/C – service manual version 0.5 Page 3
13.1 General information. ..........................................................................................................51
13.2 Check-up if vacuum is insufficient. ...................................................................................51
13.3 Tube connection diagram...................................................................................................52
14. REPLACEMENT PROCEDURES............................................................................... 53
14.1 Cover..................................................................................................................................53
14.2 Main PCB...........................................................................................................................54
14.3 Front cover. ........................................................................................................................54
14.4 Output filter PCB. ..............................................................................................................55
14.5 Vacuum PCB......................................................................................................................55
14.6 Keyboard PCB. ..................................................................................................................56
14.7 Metal shield........................................................................................................................56
14.8 Display. ..............................................................................................................................57
SPARE PARTS ............................................................................................................. 58
15.
16.
SCHEMATICS.............................................................................................................. 61
Phyaction Guidance E/C – service manual version 0.5 Page 4
2. GENERAL INFORMATION
2.1 Introduction.
The Phyaction Guidance E/C is an advanced 2 channel appliance for electrotherapy, offering a wide range of current types which can be applied by means of normal electrodes or via the integrated vacuum unit. Compared with the Guidance E, the Guidance C has an additional integrated ultrasound module. As a member if the I.M.S group, it is built according to the newest requirements concerning the Medical Device Directive.
This manual is written for service engineers, who are authorized by GymnaUniphy nv. It gives a complete and accurate picture of the Guidance E/C. In doing so, it will hopefully help you to reach your goal: to form a correct diagnosis and to solve the client’s problem as thoroughly as possible.
2.2 Information.
If you require additional information, feel free to contact us.
GymnaUniphy nv. Service department Pasweg 6a 3740 Bilzen Belgium
Tel service dept: ++32/89510560 Fax service dept: ++32/89510561
E-mail service dept: service@gymna-uniphy.com
2.3 Safety aspects.
2.3.1 Electrical safety.
The equipment can only be used in areas with provisions in accordance with current statutory requirements. Pay particular attention to the use of protective earth, otherwise the patient leakage current can rise above the permitted limit for type BF equipment.
Phyaction Guidance E/C – service manual version 0.5 Page 5
2.3.2 Explosion safety.
The equipment is not suitable for use in areas where flammable gasses or vapours are present. Therefore, remove the mains plug from the socket before the area in which the equipment is located is disinfected, since some disinfecting solutions evaporate and subsequently form an explosive mixture.
2.3.3 Operational safety.
- Using the equipment in the vicinity of short wave or microwave equipment can influence the output of the unit. Using this equipment when high frequency surgical equipment is connected to the patient at the same time can result in burning under the electrodes.
- Patients who have electrical implants (i.e. pacemaker) may only be treated following medical advice.
- The equipment is not suitable for use in damp areas.
- The equipment may not be disinfected or sterilised.
- The equipment contains a number of safety systems that operate independently of the microprocessor.
When the safety system detects a fault during electrotherapy the delivery of current is interrupted
within a few milliseconds and it is impossible to perform treatment using the equipment. The safety of the patient is therefore guaranteed. Whenever the equipment is switched on (using the main switch) the microprocessor checks the entire safety system for correct operation.
2.3.4 Use of the appliance.
The equipment and accessories should only be used by authorised personnel and in accordance with all instructions included in these operating instructions. The Phyaction Guidance is only to be used for electrotherapy.
2.3.5 Product documentation.
We strongly recommend reading the Guidance Guideline carefully, in order to understand and solve questions of the end user.
2.3.6 Radio interference suppression and electromagnetic compatibility.
This equipment meets the guidelines for ISM equipment relating to electromagnetic compatibility and is radio interference suppressed according to VDE 0871-B. Also see paragraph 1.2.3 Operational safety, concerning the use of the equipment in the vicinity of short wave and microwave equipment.
2.3.7 Medical device directive (MDD)
This device complies with the essential requirements of the Medical Device Directive of the European Committee (93/42/CEE ) as most recently changed.
Phyaction Guidance E/C – service manual version 0.5 Page 6
2.4 Installation.
2.4.1 Incoming inspection.
Check that the equipment has not been damaged during transportation and that the accessories are intact and complete. In the event of damage and/or defect you should inform your supplier.
2.4.2 Mains voltage.
Your appliance can be run off the mains at a nominal voltage of 110, 115, 127, 220, 230 or 240 Volt AC, 50-60 Hz. On the bottom of the appliance, you will find the mains voltage selector
33
to set the correct mains voltage. Check if the voltage is selected correctly (setting of a lower value than the value which should be used in your region can lead to irreversible damage of the equipment). You can use a coin to turn the switch.
2.4.3 Functional test.
During production the equipment is tested for electrical safety. Whenever the equipment is switched on, the processor performs an extensive test to ensure that the equipment is operating correctly. In addition you must check whether the display and the indicator lamps are operating correctly. If this is not the case, then you must not use the equipment and you must contact your supplier. If you can’t read or if it is difficult to read the display, then press the system adjustment button 12 and select option contrast. Use the black ¿ button to darken the text or the black À button if you want to make the text lighter.
2.4.4 Selecting the operating language.
You have the possibility to change the operating language by depressing system adjust button 12 and selecting the language option. You have the choice from various languages. Once selected, the equipment will use the language you have chosen.
2.4.5 Location and transportation.
The equipment must be set up horizontally and stable. You must ensure that the perforated sections on both sides of the casing are not covered up, thus hindering air circulation. Objects must not be placed on the equipment and you must ensure that no liquid enters the equipment. Empty the watercontainer of the vacuum part before transportation of the unit. Use the original packaging, if sending of the unit is necessary.
The appliance is capable, while packed for transport and storage, of being exposed for a period not exceeding 15 weeks to environmental conditions not outside the following ranges:
• an ambient temperature range of -20ºC to +60ºC;
• a relative humidity range of 10% to 100%, including condensation;
• an atmospheric pressure range of 500hPa to 1060 HPa.
Phyaction Guidance E/C – service manual version 0.5 Page 7
3. DESCRIPTION OF CONTROLS AND CONNECTORS.
3.1.1 Output connectors and control keys ( drawing unit on last page of service manual).
Tilting display
1.
2. Blue keys for menu option or parameter selection
Blue keys > and < for scrolling through the lists
3.
Key for increasing or setting a parameter
4.
Key for decreasing or setting a parameter
5.
6. Key for channel choice A
Key for channel choice B
7.
Amplitude controller for channel A
8.
Amplitude controller for channel B
9.
10. Therapy menu key
Guidance menu key
11.
12. Memory key
System settings key
13.
14. Help key ?
‘Go back’ key
15.
16. Pause key
Stop key
17.
18. Output channel A for plate electrodes
Output channel B for plate electrodes
19.
20. Connections for the vacuum electrodes for channel A
21. Connections for the vacuum electrodes for channel B
Yellow pilot lamps, light when the channel concerned can produce current output
22.
Vacuum controller
23.
Stand-by lamp indicating that the appliance is connected to the mains and that the appliance is
24.
turned on Main switch
25.
Fuse holder
26.
Mains entry
27.
Label with appliance data
28.
Connector to connect to the potential compensating mains
29.
Drain tube of the water reservoir
30.
Vent hole
31.
RS 232 connector for service purposes
32.
Mains switch
33.
Patient cable
34.
Plate electrodes
35.
Vacuum tubes
36.
Phyaction Guidance E/C – service manual version 0.5 Page 8
3.2 Display indication overview
Selected channel
Parameters of the selected
channel
Recommended amplitude (for
programs from the
Objectives / indication
list)
Option line, with the blue buttons
under the display the desired option
can be selected
Title of the screen; it indicates which
option you chose for
treatment
presetting the
Program
number
Symbol representation of the selected current
Arrow to the right
indicates that you can
scroll with the button >
Window channel A with
data about:
• remaining treatment time
• activated electrode
• polarity
• set amplitude
• current amplitude
• (bargraph)
• CC / CV
Window channel B; is empty here, since
channel B is not
activated.
Sometimes used as well
for the graphic
representation of the
current
Phyaction Guidance E/C – service manual version 0.5 Page 9
3.3 Technical specifications.
- Number of memory places 500 - 999
- Languages: West European: English, German, French, Dutch South European: Italian, Spanish, Portuguese, English
- Treatment time: 0 - 60 minutes
- Dimensions : 424 x 308 x 163 cm
- Weight: 9 kg
- Insulation class: I type BF
- Voltage: 110, 127,220, 230 of 240 Volt AC, frequency 50 - 60 Hz, settings via an external switch
- Power consumption: maximum 96 VA
- Help screen for explanation on the selected electrotherapeutic current or parameter
- 2 independent channels with possibility to set different therapy forms per channel
- Extensive indication list with recommended therapy programs
- Sequential therapy forms
- Possibility to set various system settings and program parameters to the personal preference
- Built-in cable and electrode test
- Solid metal casing (Faraday’s cage)
- Cover: ABS
Ultrasound output: probe model 891 ERA: 0,6 cm² at 1 MHz ERA: 1,0 cm² at 3 MHz Frequency: 1 and 3 MHz BNR < 5 Pulsfrequency: 100 Hz Duty Cycle: 10%, 20%, 30%, 40%, 50%, 100%
Ultrasound output: probe model 892 ERA: 4,0 cm² at 1 MHz ERA: 4,8 cm² at 3 MHz Frequency: 1 and 3 MHz BNR: <8 Pulsfrequency: 100 Hz Duty Cycle: 10%, 20%, 30%, 40%, 50%, 100%
3.4 Different symbols.
3.4.1 Symbols on the front of the Guidance E/C
Therapy menu
Guidance menu
Memory
System settings
Help ?
Go back
Stop
Pause
Amplitude
Phyaction Guidance E/C – service manual version 0.5 Page 10
3.4.2 Symbols on the right side of the Guidance E/C
Fuse
3.4.3 Symbols on the left side of the Guidance E/C
Input / output port (for service purposes)
Attention, sensitive for electrostatic discharges
3.4.4 Symbols on the back of the Guidance E/C
Water outlet
Do not open device
Equipotentiality
3.4.5 General symbols
Electrotherapy
Sequential currents
Iontophoresis
Channel A
Channel B
Alternating channels
Channel A+B
Treatment time
Plate electrode
Vacuum electrode
3.4.6 Symbols current groups
TENS currents
Unidirectional currents
NMES currents
Diadynamic currents
S-D curves, Rheobase /
Chronaxie / AQ
Phyaction Guidance E/C – service manual version 0.5 Page 11
3.4.7 Symbols currents
Direct current
Iontophoresis
Medium frequency rectangular current
Rectangular pulsed current
Triangular pulsed current
Conventional TENS
Low frequency TENS
Brief intense TENS
Random TENS
Burst TENS
Rectangular surge current
Triangular surge current
Biphasic surge current
Biphasic intrapulse interval surge current
2-pole interferential surge current
Russian stimulation
Classical interferential surge current
MF (Diadynamic)
RS (Diadynamic)
DF (Diadynamic)
CP (Diadynamic)
LP (Diadynamic)
2-pole interferential current
Isoplanar vector field
Dipole vector field
Classical interferential current
Rheobase and Chronaxie
Rheobase and A.Q.
S-D curve rectangular pulse
S-D curve triangular pulse
S-D curve rectangular and triangular pulse
CH
AQ
S-D
S-D
S-D
3.4.8 Parameter symbols
Polarity for plate electrodes red-, red+
Alternating polarity for plate electrodes
Polarity for vacuum electrodes
Alternating polarity for vacuum electrodes
Vacuum rhythm: continuous
1,5 s high, 1,5 s low
1,5 s high, 3 s low
1,5 s high, 4,5 s low
Phyaction Guidance E/C – service manual version 0.5 Page 12
4. UNIT SELF TEST.
The self test checks proper functioning of the product, especially the safety circuits, and is activated every time the unit is switched on. The tests are performed by the main micro-controller in combination with the safety micro-controller and take approximately 3 seconds.
When one or both of the controllers detect an error, the output will be disabled. A message will be shown to the user.
The Guidance E/C has a safety relay (RLY13). This relay (Normally Open) is integrated in the applied part of channel A and Channel B (same relay). In case of a problem, the safety relay will be switched off immediately and the patient becomes disconnected from the unit.
The safety relay driver circuitry is accessible to the main microprocessor for 3 seconds after power up of the unit. After this period the main micro-controller will not be able to switch the electrotherapy safety relay on any more. Both the main and the safety micro-controller are able to switch the electrotherapy safety relay off (the safe state).
During the selftest of the unit, the following items are checked:
1. Main controller test.
2. Safety controller test.
3. Safety software test.
4. Electrotherapy DAC test Channel A
5. Electrotherapy DAC test Channel B
6. Electrotherapy relay test.
7. Electrotherapy safety comparator test.
8. AC/DC relay test.
9. CC/CV mode test.
.
Phyaction Guidance E/C – service manual version 0.5 Page 13
5. CIRCUIT DESCRIPTION
5.1 Main PCB (ELUS004-L100).
The main PCB contains most of the electronic circuits of the Phyaction Guidance E/C. Since the layout of the PCB is mainly SMD based, most repair works can only be done by GymnaUniphy nv. Limited repair works may be done only For this reason, it is strongly recommended to keep at least one main PCB in stock, in order to solve most problems in the most efficient way.
/ The main PCB of the Phyaction Guidance E/C is exactly the same as the main PCB of the Gymna Combi 500/Duo500. Some installed components are not used in the Guidance/C but only in the Combi 500.
5.1.1 Power supply.
The mains voltage is applied to a ringcore transformer so that one single voltage of 24 VAC appears at TP59. However, due to tolerances on the line voltage, the output voltage of the transformer may vary between +21 VAC and + 40VAC. The secondary of the transformer has a fuse of T 5A L (F1) that is installed on the main PCB.
after the permission of GymnaUniphy nv.
Phyaction Guidance E/C – service manual version 0.5 Page 14
A SMPS supply, built around U2 and TR1, is used to provide the supplies for the amplifier circuits (+/- 18 V). These +/- 18 V signals are regulated to several other DC voltages by linear voltage regulators:
+ 18VDC TP1 + 15VDC TP11 + 12VDC TP2
- 5VDC TP4
- 15VDC TP72
- 18VDC TP3
- 22 VDC TP73 (non stabilized for LCD contrast)
The +18 V and –18 V are used as supply for the amplifier circuits. Therefore they are constantly monitored by U45. In case of a strong deviation, the voltage lockout (UVLO) signal becomes ‘LOW’, the safety relay will be switched off and an error will be generated. The UVLO signal is connected to the safety processor.
Since the +18V is used in the feedback loop for the SMPS, the –18V may fluctuate. In order to keep this voltage within the limits, there is a clamp system (built around Q14) installed onto this supply.
VCC (+5 VDC) is also generated by a SMPS built around U30. The VCC is also constantly monitored (U46). If this voltage goes below 4.75 V, there will be a reset signal (POR) and the safety system will be activated. The POR signal is directly connected to the microcontroller.
5.1.2 Micro-controller Circuits.
The 16 bit micro controller (U3: Siemens C167) is the heart of the system that controls and drives all the other circuits and signals, together with the safety controller (U36: PIC 16C74)
The program software is stored in a flash memory (U54, U55: AM 29F800). An upgrade of this software can only be done by means of a PC, which must be connected to the unit in order to download the software (chapter x). The actual version of the software is displayed in the start-up screen.
The micro-controller uses external RAM (U42 and U41: 256K each).
A separate display controller (U49: SED 1353) + RAM (U39 and U40: 256 K each) perform the controls of the LCD display.
U50 is a programmable peripheral interface IC which drives mainly the relay circuit.
Other components near the microcontroller circuits are:
Temperature sensor RT1 the fan in the following way:
- Temperature > 55°C: switch on fan
- Temperature < 45°C: switch off fan
- Temperature > 98°C: error and switch off all amplifier circuits.
: measuring the temperature of the heatsink, which controls the working of
Phyaction Guidance E/C – service manual version 0.5 Page 15
U52: reading OTP values (not used in Phyaction Guidance E/C).
Microcontroller guard
Amplitude generation circuits output signal of U14 is the reference value for U24 that produces the amplitude modulated (AM) signals for the LF currents (MF, DF, CP, LP, IF).
The output signals are connected to the signal processing circuits.
5.1.3 Safety control circuits.
The main goal of the safety circuit is to protect the patient and the Electrotherapy circuit from too high currents. In case of an error, the safety relay is switched off and a error code is generated. A special safety controller (U36: PIC16C74) monitors and controls all the safety components used in the Guidance E/C.
/ Note that even when an error is not longer occurring, the output state of the RS flipflop stays ‘low’ and the safety relay remains off. The unit must be restarted in order to continue any treatment.
The following items are constantly checked:
Measured current in relation to the set intensity:
Comparator U1 and DAC U25 guard the output level. U1 compares the output signals from the current measuring circuit (CUR_A SAF/CUR_B SAF) with the reference voltages (FDBACK_SAFA/FDBACK_SAFB). These reference voltages are generated by the safety DAC U25 and are setup by the microprocessor U36. In case of a problem, the PROTECTION signal will go ‘LOW’ and the safety relay is switched off. The limit values are different for each current waveform plus they depend on the set intensity level. The safety controller sets the limit for each current waveform via the AD converter U 25.
Proper functioning of both the microcontrollers:
If the PIC microcontroller detects a problem with the Siemens microcontroller, it will switch off the safety relay by making the MC_SRY_off signal ‘high’ (microcontroller safety relay off). If, on the other hand, the Siemens microcontroller detects a problem with the PIC, it will switch off the safety relay by making the S_SRY_off signal ‘high’ (Siemens safety relay off).
VCC:
In case the VCC (5V) goes below 4.75 V, an error is generated via the POR line which causes the safety relay to switch off.
Rotary channel A and B:
The value of the encoders (= intensity knob) are measured by the PIC and compared by the Siemens microcontroller.
component (U 64):
: U14 produces a DC signal in relation to the demanded intensity. The
Phyaction Guidance E/C – service manual version 0.5 Page 16
In case of a difference, the safety relay is switched of and an error is generated.
The safety controller also reads and processes the values of the keyboard.
5.1.4 Signal processing circuits.
/ The signal processing and stimulation circuits are identical for channel A and channel B. Only the circuits for channel A are explained.
The signal processing circuits are built around U11 (CH A). This IC is a programmable sinusoidal generator, producing a sinusoidal signal of a determined frequency. The form of the amplitude is determined by DAC U24 and U14.
Depending on the type of current the therapist has chosen, the multiplexing IC U34 (CHA) will select the right input and connect it to the amplifier circuits (Pow A):
X0: sinusoidal signal sometimes modulated in amplitude (depending on current waveform). X1: fixed voltage. X2: DAC_A: amplitude modulated signal for diadynamic currents (without sinusoidal component). X3: inverted signal of X0.
5.1.5 Stimulation circuits.
After the amplitude and/or the waveform of the signal are generated the stimulation circuit amplifies it, turns it into a CC or CV signal and if necessary changes the polarity and/or rectifies the signal.
Basically there are four possible hardware configurations, and the amplifier circuit can be redrawn according to each configuration.
Configuration 1: mode CC, pulsed (tens, rectangle, triangle, diadynamic). Configuration 2: mode CC, continuous (interference, direct continuous). Configuration 3: mode CV, pulsed (tens, rectangle, triangle, diadynamic). Configuration 4: mode CV, continuous (interference, direct continuous).
Phyaction Guidance E/C – service manual version 0.5 Page 17
Configuration 1
The circuit can be redrawn as in the figure below.
The output of U9 (TDA 2040) is a DC signal and is connected to the middle connection of the transformer. One side of the transformer is connected to Q1 and the other side is connected to Q2. The gates of Q1 and Q2 are connected to POS_A and NEG_A respectively. The soures of Q1 and Q2 are coupled via Q7 and R3 to ground. The current through Q7 is controlled by the output of U65. IPAA is a measure for the current through Q7 and so controls the output amplitude. The measured current (over R3) is fed back to the input of U65, this way the current is kept constant. In case of a rectangular or triangular signal the signal at the secondary of the transformer will be rectified.
Configuration 2:
In comparison with configuration 1 , Q1 will be excluded from the circuit and POS_A and CURRENT_A will be continuous ‘HIGH’. The amplitude of POW_A is a measure for the output current and the current is fed back via R3 to the input of U9, in order to keep the current continuous.
Phyaction Guidance E/C – service manual version 0.5 Page 18
Configuration 3:
It is similar to configuration 1, but with the difference that the signal POW_A is not a fixed value, but is variable and a measure for the output amplitude and shape. Just as with CC, the maximum current is limited by IPAA.
Configuration 4:
Q1 is excluded and the gate of Q2 is kept ‘HIGH’ and there are two feedback circuits, namely the voltage at the output of U9 via R109 and the current through R3 which will give the output stage a virtual internal resistance. Short circuiting the output, the output current will not exceed its maximum value.
5.1.6 Current measuring circuits.
At the output the current is measured by the current measurement circuit. The current measuring circuit translates it into a DC level that serves as an input for the Safety control circuit and for contact detection.
5.2 Output circuits.
Phyaction Guidance E/C – service manual version 0.5 Page 19
The output module consists of 2 electrotherapy channels and 2 vacuum channels (with 4 vacuum connections). Each configuration of electrotherapy and vacuum is possible.
The output PCB contains of the output circuitry for the use of electrotherapy with or without vacuum. Whether vacuum is used or not is determined by the micro controller via several relays. Both channels can be switched off separately via micro controlled valves. The vacuum can be set between 50 and 400mBar in the continuous mode. In the pulsating mode the vacuum can be set between 60 and 600mBar. The level of the vacuum is controlled by means of the vacuum pump and an air inlet via a valve. The water that comes into the system is collected into a water reservoir. The water reservoir can be emptied via an external tube.
5.3 Console circuits.
The console module is the module that forms the interface to the user. The interface consists of:
• A rubber keypad that makes the contact via a membrane keyboard on the console PCB. The matrix of the keys is controlled by the micro controller.
• Two encoders directly controlled by the micro controller
• The converter for the backlight controller
Phyaction Guidance E/C – service manual version 0.5 Page 20
5.4 Ultrasound circuits (only for Guidance C)
5.4.1 PLL
The frequency generator is controlled by the micro controller and it contains a voltage controlled oscillator and a PLL (phase locked loop).
Each ultrasound crystal has different characteristics. Every crystal is measured during production, and an optimal working frequency and the ‘bad contact’ frequency is determined. This means that the ultrasound output stage works on different frequencies according to which head is connected. In order to ‘program’ different frequencies, a PLL is used in combination with a VCO.
To obtain a symmetrical steering signal for the power stage the modulator switches its outputs with half the input frequency. Also the modulator mixes the duty signal synchronously with the ultrasound frequency to prevent spikes. An amplitude modulation with 100% modulation depth (the signal being switched on and off) is the result of this mixing.
The calibration values of each ultrasound head are stored in an OTP, which is installed inside the ultrasound head. In case of a replacement of the crystal, the OTP has to replaced as well (comes with the crystal)
5.4.2 Voltage controller.
A pulse controlled downward converter voltage controller is used to convert the +24V to the desired ultrasound voltage. The voltage controller is made in such a way that its output voltage is linear proportional to its input voltage VUS_set. Thus the micro controller can adjust the ultrasonic power by setting VUS_setproportional to the square root of the desired output power.
5.4.3 Power stage
The power stage is a switched balance class-D end stage. Power MOSFETs are used as switching elements. The MOSFETs are driven by buffers (U506) that also take care of a small delay in driving the MOSFETs, to prevent them of being active simultaneously. If either one of the MOSFETs has become defective, both of them should be replaced.
Phyaction Guidance E/C – service manual version 0.5 Page 21
5.4.4 Impedance matching
The ultrasound crystal is mainly a capacitive load. Its impedance differs, among other things, with the size of the crystal and its operating frequency. For this reason the micro controller can match the impedance by switching one or two inductors and when necessary capacitors in the output stage.
5.5 RS 232 communication.
This interface is used for:
• externally programming the device (service)
• internally programming the device (production)
• future applications
The signals that are used for sending and receiving data from and to an external device, must be isolated according to IEC601. Also the supply must be isolated. The supply is isolated via a transformer and the signals are isolated with opto-couplers. At both sides of the opto-couplers a send/receive IC is necessary to comply to the standard levels.
The maximum speed of the connection is mainly determined by the speed of the opto-couplers which is 38400 bits/sec (baud rate). Downloading new software will take approximately 10 minutes.
5.6 Vacuum unit.
5.6.1 General information.
The Guidance E/C has a 2 channel integrated vacuum module with the following specifications:
Continuous mode: 50 Æ 320 mBar +/- 10% on maximum level. Pulsed mode : 65Æ 480 mBar +/- 10% on maximum level. Rhytm on/off time (sec): 1.5/6.0 ; 1.5/4.5 ; 1.5/3.0 ; 1.5/1.5
The vacuum module has the following components:
- Water reservoir.
- Pump.
- Rhythm valve.
- Valve channel A.
- Valve channel B.
- Vacuum PCB.
Since the electrotherapy channels work completely independent, it also goes for the vacuum channel. This means that the therapist is able to work eg. on channel A with electrodes and on Channel B with vacuum.
Switching on/off the vacuum can be done by means of a parameter selection on the therapy menu. The vacuum pressure for both the channels must be set by means of the vacuum knob on the front side of the unit.
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5.6.2 Vacuum circuits.
The vacuum is measured by means of the vacuum sensor S101 (wheatstone bridge). The measured value is compared with the set value (VACSET ) by U102A and a PWM generator (U102B) controls the pump when necessary. The vacuum intensity can be set by means of a knob on the front of the unit (VACSET signal).
When the measured vacuum is higher than the set vacuum, the rhythm valve will be open until the vacuum reaches its normal level (Vvac)
Both the channels A and B have their own valve which means that each vacuum channel can be selected separately (VAC/NRM A and VAC/NRM B). When a pulsed vacuum treatment is selected, the V-Rhythm signal will open and close the rhythm valve in accordance with the pulse selection.
All valves are Normally Closed and will be opened by means of a 24 VDC signal.
The water level in the reservoir is checked on constant base. A block signal, produced by U107, is presented to one of the metal detection pin inside the reservoir. If the water reaches a certain level, this signal will be transmitted to the second detection pin. This signal is picked up by U106, and a signal is given to the microprocessor via the H2O level line.
If the microprocessor detects a full reservoir, the following message on the screen appears ‘water reservoir full’. It is still possible to continue the treatment. If the message appears before the treatment is started, it is impossible to switch on the vacuum unit.
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