S5 Dual Pressure Module Technical Reference Manual June 2001

Table of contents

TABLE OF CONTENTS Dual Pressure Module, M-PP TABLE OF CONTENTS

i

TABLE OF FIGURES

ii

Introduction

1

1

2

Specifications

1.1 General specifications ...2 1.2 Typical performance ...2 1.3 Technical specifications ...2

2

Functional Description

3

2.1 Measurement principle ...3 2.2 Main components...3 2.2.1 PP board...4 2.3 Connectors and signals...7 2.3.1 Module bus connector ...7 2.3.2 Front panel connectors ...8 2.3.3 Other connectors...8

3

Service Procedures

9

3.1 General service information...9 3.2 Service check ...10 3.2.1 Recommended tools ...10 3.3 Disassembly and reassembly ...13 3.4 Adjustments and calibrations...14 3.4.1 Invasive pressure calibration...14

4

Troubleshooting

15

4.1 Troubleshooting chart ...15 4.2 Troubleshooting flowchart ...16

5

Service Menu

17

5.1 PP menu...18 5.2 PP calibrations menu ...19

6

Spare Parts

20

6.1 Spare parts list ...20 6.1.1 Dual Pressure Module, M-PP, Rev. 00 ...20 6.1.2 Dual Pressure Module, M-PP, Rev. 01 ...21 6.1.3 Front panel stickers for AS/3 modules (square buttons) ...21 6.1.4 Front panel stickers for S/5 modules (round buttons)...21

7

Earlier Revisions

23

APPENDIX A

25

Service check form

A-1

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TABLE OF FIGURES Figure 1

Dual Pressure Module, M-PP... 1

Figure 2

Dual Pressure Module, M-PP, front panel... 3

Figure 3

PP board block diagram... 4

Figure 4

Pressure transducer principle of operation... 5

Figure 5

Serial communication and opto isolation sections ... 6

Figure 6

Module bus connector (X1) ... 7

Figure 7

M-PP troubleshooting flowchart ...16

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Dual Pressure Module, M-PP

INTRODUCTION This section provides information for the maintenance and service of the Dual Pressure Module, MPP. The M-PP module is a single width plug-in module designed for use with the S/5 monitors. The Dual Pressure module provides invasive blood pressure (InvBP) measurement.

Figure 1

Dual Pressure Module, M-PP

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1

SPECIFICATIONS

1.1 General specifications Module size, W × D × H Module weight Power consumption

37 × 180 × 112 mm / 1.5 × 7.1 × 4.4 in 0.35 kg / 0.8 lbs approximately 3.5 W

1.2 Typical performance Measurement range Accuracy Zero adjustment range Calibration range Scales Sweep speed

-40...+320 mmHg ±5 % or ±2 mmHg, whichever is greater ±150 mmHg ±20 % Upper limit is adjustable between 10 and 300 mmHg in steps of 10. Lower limit is 10 % of selected upper limit below zero. 12.5, 25, 50 mm/s

DIGITAL DISPLAY Range Resolution

-40...+320 mmHg ±1 mmHg

WAVEFORM DISPLAY Range

-30...+300 mmHg

HEART RATE FROM ARTERIAL PRESSURE Measurement range 30...250 bpm Resolution 1 bpm Accuracy ±5 bpm or ±5 %, whichever is greater

1.3 Technical specifications Accuracy Transducer and input sensitivity Nonlinearity Filter Zero set accuracy Calibration resolution Zero time

±5 % or ±2 mmHg, whichever is greater 5 µV/V/mmHg, 5 VDC, 20 mA max current < 1 %, 0...200 mmHg < 2 %, -40...0 and 200...320 mmHg 0...4 - 22 Hz adjustable ±1 mmHg ±1 mmHg < 15 sec

Protection against electrical shock

Type CF defibrillation proof

DIGITAL DISPLAY AVERAGING Art and P1 digital displays are averaged over 5 seconds and updated at 5 second intervals. All other pressures have respiration artifact rejection. NOTE: The accuracy of the measurement may be different from that specified, depending on the transducer/probe being used. Please check the transducer/probe specification.

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2

FUNCTIONAL DESCRIPTION

2.1 Measurement principle To measure invasive blood pressure, a catheter is inserted into an artery or vein. The invasive pressure setup, consisting of connecting tubing, pressure transducer, an intravenous bag of normal saline all connected together by stopcocks, is attached to the catheter. The transducer is placed at the same level with the heart, and is electrically zeroed. The transducer is a piezo-resistive device that converts the pressure signal to a voltage. The monitor interprets the voltage signal so that pressure data and pressure waveforms can be displayed.

2.2 Main components The main components of the Dual Pressure Module, M-PP, are a PP circuit board, a front panel and a box. The front panel includes two Nicolay-type connectors, P5 and P6, and two direct function keys, Zero P5 and Zero P6 for pressure zeroing. Communication between the Dual Pressure Module and the Central Unit is an RS485 serial interface. The power supply voltages to the Dual Pressure Module are generated in the power supply section of the Central Unit. All electrical connections between the Dual Pressure Module and the Central Unit are via a 25-pin D-connector at the back of the module. Zero P5 P5

Zero P6 P6

Figure 2

Dual Pressure Module, M-PP, front panel

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2.2.1 PP board

Module bus connector Module data

Module reset RS485 Driver for module reset

RS485 Driver for data

Opto isolation

Power for Communication Power reset

Power for module Power nonisolation section Isolation transformer

Patient isolation

Reset

µprocessor Module bus data

RAM internal 2K external 16K EPROM 48K RS communication

Power isolation section

Non volatile memory AD-converter -8 chn -12bit

Press AD

INV PRESS measuring unit

Front panel keys

Patient connectors Figure 3

PP board block diagram

Microprocessor unit The microprocessor uses the Intel 80C196KC-16 CPU which includes three A/D converters and a UART. The microprocessor uses external memories, an 8-bit data bus, a 16 MHz oscillator, an open collector reset, and a watchdog timer. The three A/D-converters within the CPU convert the analog input signals to digital. The internal UART communicates and transfers data between the module and the CPU board in the monitor.High speed I/O is used to obtain the pulse control sequence necessary for pulse oximetry measurement. It receives its timing clock signal from the 16 MHz oscillator.

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Invasive blood pressure measurement unit An isolated +5 V supply is connected to the input of the pressure transducer bridge circuit. From the bridge circuit output a differential voltage, which depends on blood pressure and input supply voltage, is calculated using the following formula: Uout = Uin × Pressure × 5 V where Uin = 5 V Uout = 25 V × Pressure [mmHg] Pressure amplification is performed by the instrumentation amplifier. The gain of the amplifier is set so that the level of the signal transferred to the A/D converter stays within the measurement range even when there are circumstantial offsets or offsets caused by the pressure transducer. The input filter before the amplifier attenuates high frequency disturbances. Vin

Pressure transducer Instrumentation amplifier Vout

Input Filter

G to AD converter

Figure 4

Pressure transducer principle of operation

Serial communication Serial communication between the Dual Pressure Module and the Central Unit is via an RS485 type bus. The communication bus drivers are powered from the Central Unit Module Bus. The module isolation section (+5 V) is powered from the isolated power supply. The buffers of the serial communication drivers are controlled by a reset signal such that when the reset is active the drivers do not transfer data. In addition to the RS485 reset there is a logic power-up reset, which holds for approximately 500 ms regardless of the state of the RS485 reset. A time constant determines the power-up reset time. The power-up reset also prevents the module from sending data to the Module Bus. The data transmission rate is 500 kbps.

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Send data

Receive data Send data send/receive Reset

Figure 5

RS485 Driver NData

Opto isolation

send/receive

Reset

RS485 Driver

Reset in NReset in

to central unit (module bus)

Data

Receive data

Patient Isolation

to module prosessor

Datex-Ohmeda S/5 monitors

Serial communication and opto isolation sections

Isolated section There are two opto isolators, one for data and one for the reset signal. Signals are processed on logical high-low levels even though the output of the opto isolators in the isolation section are analog signals. The reset line is an open collector type with a pull-up resistor so that the microprocessor is able to use its internal watch-dog function. Power supply section The module isolated supply voltage is developed from the +15 Vdirty (non-isolated) supply from the Central Unit power supply. The isolated power supply is a switched-mode circuit, where an FET switch is controlled by an oscillator using a bipolar timer. The frequency of the oscillator is approximately 30 kHz with a pulse ratio 50 %; switching of the FET switch is slow to suppress spurious interference. A special isolation pulse transformer is used in the circuit. The transformer secondary circuit uses normal linear regulators except for +5 V which uses a low drop type linear regulator.

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2.3 Connectors and signals 2.3.1 Module bus connector

13

1

25

14

Figure 6

Module bus connector (X1)

Pin No

I/O

Signal

1

I

RESET_RS485

2

I

-15 VDC

3

I

+15 VDIRTY

4 5

I I/O

+15 Vin NDATA_RS485

6

I/O

DATA_RS485

7

Ground

8

I

NRESET_RS485

9

I

CTSB

10

O

RTSB

11

I

RXDB

12

O

TXDB

I

+32 VDIRTY

13 14

Ground

15

I

GroundDIRTY

16

I

CTSC

17

O

RTSC

18 19

I O

RXDC TXDC

20 21

ON/STANDBY O

22

PWM_ECG RXDD_RS232

23

TXDD_RS232

24

I

+5 VDCin

25

I

+5 VDC

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2.3.2 Front panel connectors Pressure connectors (P5, P6)

3 6 1

4

7

5

8

2

Pin no.

9

0

Signal

1

Pressure 5/6 +

2

Pressure 5/6 -

3

Polarization - (ground)

4 5

Polarization + Not connected

6

Not connected

7

Not connected

8

Not connected

9

Ground

10

Cable detection

2.3.3 Other connectors Keyboard connector (X3) Pin no.

Signal

Notes

1 2

N/C PSWITCH

Not connected for zeroing of P5

3

PSWITCH

for zeroing of P6

4

fGND

Floating GND

5

fGND

Floating GND

Pin no. Board

Pin no. fr.panel

Signal

Notes

X4

1

0

PCABEL

5V if cable not connected

2

4

PCURRENT

Pulsed supply to sensor

1

3

3,9

P-

Signal from the sensor

4 5

1 2

P+ fGND

Signal from the sensor Floating GND

X3 5

1

Pressure sensor connector (X4)

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5

Dual Pressure Module, M-PP

3

SERVICE PROCEDURES

3.1 General service information Field service of the Dual Pressure Module, M-PP, is limited to replacing faulty circuit boards or mechanical parts. Faulty circuit boards should be returned to Datex-Ohmeda for repair. Datex-Ohmeda is always available for service advice. Please provide the unit serial number, full type designation, and a detailed description of the fault.

CAUTION

Only trained personnel with appropriate equipment should perform the tests and repairs outlined in this section. Unauthorized service may void warranty of the unit.

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3.2 Service check These instructions include complete procedures for a service check. The service check is recommended to be performed after any service repair. However, the service check procedures can also be used for determining possible failures. The procedures should be performed in ascending order. The instructions include a check form which should be filled in when performing the procedures.

? in the instructions means that the check list should be signed after performing the

The mark procedure.

The procedures are designed for monitors with S/5 monitor software of revision 01. However, most of the procedures also apply to monitors, which contain some other monitor software type/revision.

3.2.1 Recommended tools Tool

Order No.

Notes

Patient simulator Pressure manometer InvBP transducer Screwdriver •

Detach the module box by removing the two screws from the back of the module. Be careful with the loose latch and spring locking pin.

1.

Check internal parts: •

screws are tightened properly

•

cables are connected properly

•

all socket mounted IC’s are inserted properly

•

EMC covers are attached properly

•

there are no loose objects inside the module

? 2.

Check external parts: •

the front cover and the front panel sticker are intact

•

all connectors are intact and are attached properly

•

the module box, latch and spring locking pin are intact

? •

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Reattach the module box and check that the latch is moving properly.

Dual Pressure Module, M-PP

•

Turn the monitor on and wait until the monitoring screen appears. Configure the monitor screen so that all the required parameters are shown, for example:

Monitor Setup - Screen 1 Setup - Waveform Fields - Field 4 - P5 Field 5 - P6 3.

Plug in the module, M-PP. Check that it goes in smoothly and locks up properly.

? •

Preset the InvBP measurement settings:

Invasive Pressures - P5 Setup - Label - P5 P6 Setup - Label - P6 4.

Enter the service menu:

Monitor Setup - Install/Service (password 16-4-34) - Service View (password 26-23-8) Take down the information regarding PP module software by selecting SCROLL VERS and turning the ComWheel.

?

5.

Enter the PP module service menu (according to the module being tested): Modules - PP Check that the “Timeouts”, “Bad checksums” and “Bad c-s by mod” values are not increasing faster than by 50 per second. Check that the module memories have passed the internal memory test, i.e. “RAM”, “ROM” and “EEPROM” all show OK.

?

6.

Check the front panel membrane keys. Press each of the keys for at least one second. Check that the key being pressed is identified, i.e. the text on the service menu for “Button” changes from OFF to ON.

?

7.

Check that “Cable” and “Probe” show OFF. Plug the cable from an invasive blood pressure transducer into front panel connector P5. Check that the corresponding “Cable” and “Probe” messages show ON and the correct pressure waveform field appears on the monitor screen.

?

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Calibrate the InvBP channels according to the instructions in the Technical Reference Manual.

?

9.

Check the InvBP channels with a patient simulator. The settings and checks with a Dynatech Nevada medSim 300 Patient Simulator are: SENSITIVITY switch position: 5 µV/V/mmHg ECG - BASE - BPM - 60 BP - 2 - WAVE - ATM 3 - WAVE - ATM Connect channel BP2 to connector P5 and channel BP3 to connector P6. Zero the InvBP channels by pressing the zeroing keys on the module front panel. BP - 2 - WAVE - CVP 3 - WAVE - PA Check that appropriate InvBP waveforms are shown and the InvBP values are approximately 15/10 mmHg (±2 mmHg) for channel P5 and 25/10 (±2 mmHg) for channel P6.

?

10.

Perform an electrical safety check and a leakage current test.

11.

Check that the module functions normally after performing the electrical safety check.

12.

Clean the module with suitable detergent.

•

Fill in all necessary documents.

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? ? ?

Dual Pressure Module, M-PP

3.3 Disassembly and reassembly Disassemble the Dual Pressure Module, M-PP, in the following way. See the exploded view of the module. 1.

Remove the two screws from the back of the module.

2.

Pull the module box slowly backwards and remove it from the main body. Be careful with the loose latch and spring locking pin.

3.

To detach the PP board, remove the two screws, and disconnect the two ribbon cables from the front panel.

To reassemble the module, reverse the order of the disassembly steps.

CAUTION

When reassembling the module, make sure that all cables are connected properly.

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3.4 Adjustments and calibrations 3.4.1 Invasive pressure calibration Perform a pressure calibration whenever the pressure transducer (probe) is replaced with different type of transducer. 1.

Enter the PP service menu (Monitor Setup - Install/Service - Service - Parameters).

2.

Enter the Calibrations menu.

3.

Connect a pressure transducer with a pressure manometer to the P5/P6 connector. Select Calibrate P5 or Calibrate P6 from the menu. Leave the transducer at room air pressure.

4.

Press the ComWheel to start zeroing.

5.

Supply a pressure of 100 mmHg...300 mmHg to the transducer. The recommended pressure is 200 mmHg.

6.

Set the pressure on the display to match the pressure reading on the manometer and press the ComWheel. A tolerance of ±1 mmHg is allowed.

7.

The text 'calibrated' will appear on the display.

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4

TROUBLESHOOTING See also the User's Reference Manual for more troubleshooting procedures.

4.1 Troubleshooting chart Trouble

Cause

Treatment

Abnormally low pressure

Transducer wrongly positioned.

Check mid-heart level and reposition transducer.

No pressure

Defective transducer.

Check the transducer.

No pressure module plugged in.

Check the module.

No selected waveform on screen.

Check selected pressure waveforms by pressing Monitor Setup key and selecting modify waveforms. Check that pressure transducer open to patient.

“Not zeroed” message

Measurement on, channel not zeroed.

Zero the channel.

Zeroing failedmessage

Unsuccessful zeroing of P5 /P6 (number field), possibly due to pulsating pressure waveform.

Open the transducer to air and zero the channel.

Offset is > 150 mmHg.

Open the transducer to air and zero the channel.

Defective transducer.

Replace the transducer and zero the channel.

Calibration failed- Unsuccessful calibration of P5/P6 message (number field), possibly due to pulsating waveform

Turn the transducer to sphygmomanometer and try again (zeroing takes place first). Replace the transducer.

Gain is beyond the limits (± 20 % of the default gain). Out of range < 40 mmHg

Pressure measurement is beyond measurement range.

Check the transducer level. Zero the channel.

Out of range > 320 mmHg

Pressure measurement is beyond measurement range.

Check the transducer level. Zero the channel. The patient may also have high blood pressure.

Zero adj. > 100 mmHg

Offset when zeroing is > 100 mmHg (but < 150 mmHg) from the absolute zero of the module (with default gain). The waveform may hit the top of the screen and the numeric display not shown.

Check the transducer.

Out of range

Measured pressure is beyond the internal Check the transducer and its level. measurement range of the module. The waveform may hit the top of the screen and Zero the channel. the numeric display not shown. 15 Document No 8001014-1

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4.2 Troubleshooting flowchart Possibly faulty M-PP module

Take all modules out of the frame

Insert M-PP module and turn the power on

No

Does fault still appear?

Fault not in M-PP module

Yes

Enter the Service menu

No

No

Module-ID on screen?

Does another module work in the same slot?

Yes Yes

Check front panel key functions in Service menu

Yes

Do they work?

No

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Has EEPROM failed

Yes Replace the PP board

No

Check front panel unit and PP board to find fault. Replace if necessary.

Figure 7

Replace the PP board

Has InvBP measurement failed

Yes

M-PP troubleshooting flowchart

Replace the PP board

Dual Pressure Module, M-PP

5

SERVICE MENU

1.

Press the Monitor Setup key.

2.

Select Install/Service (password 16-4-34).

3.

Select Service (password 26-23-8).

4.

Select Parameters.

5.

Select PP module.

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