101 Serial Interface Connection

The 9-pin connector mounted on the rear panel provides an access port for a serial (RS-232) interface to the P-3900 Printer, or to a suitably configured personal computer. Alternatively, qualified service personnel can use the connector to send a Nurse Call signal. NOTE The Communications Selection item in monitor's Set-up Menu must be set to Printer if the P-3900 is to be used or, must be set to Trend Xfer if trend data is to be exported to a personal computer. (Set-up Menu is opened by...

102 Nurse Call

Pin 9 of the RS-232 serial interface connector provides an Alarm Out signal. Any time there is an alarm condition active in the NPB-3900, pin 9 will go to plus RS-232 level voltage (> +5 VDC), if Nurse Call Signal is set to ON in the Set-up Menu. Any time there is no active alarm condition, pin 9 will be at minus RS-232 level voltage (< -5 VDC). If in the Set-up Menu Nurse Call Signal is set to OFF, pin 9 will always be at the minus RS-232 level voltage. In order to make use of the Alarm...

103 Exporting Trend Data

In order to download trend data from the NPB-3900, communication software, such as PROCOMM , should be installed in the external computer. The transfer protocol should be set as follows Connect the NPB-3900 to the serial port of the computer using a null modem cable. Start the communication program on the computer and enter terminal emulation mode. To initiate the transfer, type tr (lower case is necessary), followed by a carriage return < cr> . If the command is not accepted, the response...

13 Npb3900 Patient Monitor Description

The purpose and function of the NPB-3900 series of patient monitors is to monitor ECG heart rate noninvasive blood pressure (systolic, diastolic, and mean arterial pressures) functional arterial oxygen saturation and temperature for adult and pediatric patients in all hospital areas and hospital-type facilities. They may be used during hospital transport and in mobile, land-based environments, such as ambulances. Refer to the NPB-3900 operator's manual for a description of the NPB-3900...

14p3900 Introduction

The P-3900 is an optional, standalone printer designed for use with the NPB-3900 patient monitor. The P-3900 communicates with the monitor using a null-modem cable connected between each device's RS-232 connector. The P-3900 contains an internal battery, which, when fully charged, will operate the printer for 3 hours (typical, at 25 C, producing fifteen 20-second printouts per hour). The P-3900 can be connected to AC power using an external power supply. The P-3900 uses the same type power...

21 Cleaning

WARNING Do not spray, pour, or spill liquid on the NBP-3900, its accessories, connectors, switches, or openings in the chassis. Do not immerse the NPB-3900 or its accessories in liquid or clean with caustic or abrasive cleaners. To clean the NPB-3900, dampen a cloth with a commercial, nonabrasive cleaner and wipe the exterior surfaces lightly. Do not allow any liquids to come in contact with the power connector or switches. Do not allow any liquids to penetrate connectors or openings in the...

22periodic Safety And Functional Checks

Nellcor Puritan Bennett recommends that the following checks be performed at least every 2 years by a qualified service technician. 1. Inspect the exterior of the NPB-3900 for damage. 2. Inspect labels for legibility. If the labels are not legible, contact Nellcor Puritan Bennett's Technical Services Department or your local Nellcor Puritan Bennett representative. 3. Verify that the unit performs properly as described in paragraph 3.3. 4. Perform the electrical safety tests detailed in...

33 Performance Tests

The battery charge and battery performance tests should be performed before monitor repairs whenever the battery is suspected as being a source of a problem. All other tests should be performed following monitor repairs. Before performing the battery performance test, ensure that the battery is fully charged (paragraph 3.3.1). This section is written using Nellcor Puritan Bennett factory-set power-up defaults. If your institution has reconfigured custom defaults, those values will be displayed.

331 Battery Charge

Perform the following procedure to fully charge the battery. Connect the monitor to an AC power source using the PS-120 or PS-240 external power supply and power cord, if needed. Verify that the EXTERNAL POWER indicator is lit. 3. Charge the battery for at least 8 hours. The battery may require a complete charge discharge cycle to restore its normal capacity. 4. To check for a full charge, perform the procedure in paragraph 3.3.2 Battery Performance Test.

333 PowerOn Self Test

Connect the monitor to an AC power source using the PS-120 or PS-240 power supply and power cord, and verify that the EXTERNAL POWER indicator is lit. 2. Do not connect any input cables to the monitor. 3. Observe the monitor front panel. With the monitor off, press the ON STANDBY button. The monitor must perform the following sequence. b. A few seconds later, the display backlight illuminates, but the display is blank. c. The Nellcor Puritan Bennett logo then appears for a few seconds, with the...

334 Hardware and Software Tests

Hardware and software testing includes the following tests applicable to the indicated models in the series. 3.3.4.1 SpO2 Testing NPB-3900 3.3.4.2 Operation with an ECG Simulator NPB-3930, NPB-3940 3.3.4.3 Verification of Pneumatic System NPB-3900 3.3.4.4 Operation with a Temperature Simulator NPB-3920, NPB-3940 3.3.4.5 General Operation NPB-3900 3.3.4.1 SpO2 Testing (NPB-3900) SpO2 testing includes the following tests. 3.3.4.1.1 Alarms and Alarm Silence 3.3.4.1.2 Heart Rate Tone Volume Control...

3345General Operation

The following tests provide an overall performance check of the system 3.3.4.4.1 Operation with a Human Subject 3.3.4.4.2 Serial Interface Test 3.3.4.4.3 Printer Verification 3.3.4.5.1 Operation with a Human Subject Patient monitoring involves connecting the monitor to a human subject for a qualitative test. 1. Connect an EC-8 sensor extension cable to the monitor. Connect a Nellcor Puritan Bennett Durasensor finger clip sensor, model DS-100A, to the sensor extension cable. Clip the DS-100A to...

3413 Patient Leakage Current with Mains Voltage on the Applied Part

This test measures patient leakage current in accordance with IEC 601-1, clause 19, for Class II, type CF equipment. In this test, 110 of mains voltage is applied between each patient connection and earth (power ground). Patient leakage current is then measured from any individual patient connection to earth. NOTE This test requires the same test cables for each patient connector as described in section 3.4.1.2. WARNING AC mains voltage will be present on the applied part terminals during this...

3421 Patient Leakage Current

This test measures patient leakage current in accordance with IEC 601-1, clause 19, for Class II, type CF equipment. Patient leakage current in this test is measured from any individual patient connection to earth (power ground). NOTE This test requires a test cable for each patient connector. For example, the ECG test cable consists of the ECG cable connector, with all the conductors shorted together, connected to a test lead from the electrical safety analyzer. Test cables for SpO2 and...

42powerup Defaults Menu

The purpose of the Power-up Defaults Menu (Table 4-1) is to allow the authorized user to create a power-up default for each setting in the NPB-3900. Power-up defaults are the settings in effect each time the NPB-3900 is powered on. Once the Power-up Defaults Menu is entered, physiological monitoring is terminated. The screen layouts do NOT display any information associated with normal monitoring operation. Use the following procedure to configure the power-up default settings for the NPB-3900...

43restoring Factory Settings

CAUTION In addition to restoring factory defaults, this procedure will also clear the contents of trend memory. NOTE Read this procedure completely before performing the first step. The following technique can be used to restore the monitor's power-up default settings which were originally established at the factory 1. With the monitor powered off, simultaneously press the Volume and Contrast buttons on the front keypad. 2. While continuing to press the Volume and Contrast buttons, power-up the...

442 System Information

This screen displays several system-related items Monitor On-time Displays the number of hours, rounded to the nearest hour, that the Main PCB has been operational. This value may not be reset. (See Note 1.) NOTE 1 Monitor on-time, backlight on-time, and battery deep discharge values are stored in nonvolatile memory. When a new Main PCB is installed, this value will be set at zero. Backlight On-time Displays the number of hours, rounded to the nearest hour, that the LCD Backlight has been...

44diagnostic Mode

The purpose of Diagnostic Mode is to allow factory, field-service, and hospital biomedical technicians access to a series of test and system-related information screens for the purpose of verifying NPB-3900 performance or troubleshooting problems. To access the Diagnostic Mode, first invoke the Power-up Defaults Menu as described in section 4.2. Then, select the menu item, Enter Diagnostic Mode. Choose Yes. The Power-up Defaults Menu will be exited and the Diagnostic Menu will appear.

54replacement Level Supported

The replacement level supported for this product is to the printed circuit board (PCB) and major subassembly or component level. Once you isolate a suspected PCB, follow the procedures in Section 6, Disassembly Guide, to replace the PCB with a known good PCB. Check to see if the trouble symptom disappears and that the monitor passes all performance tests. If the trouble symptom persists, swap back the replacement PCB with the suspected malfunctioning PCB (the original PCB that was installed in...

562 Error Codes

When the NPB-3900 detects an error condition, the monitor shows an error code on the display screen. If such an error occurs during monitoring operation, an audible alarm tone will sound, as well. Press the ALARM SILENCE button to terminate the audible alarm tone. When an error code appears on the display, a number in hexadecimal representation indicates the nature of the error. Additionally, Diagnostic Mode may be used to gain access to an error code record, stored in nonvolatile memory, of...

5621 Serviceable Hardware Error Codes

In Table 5-3 are error codes that correspond to hardware problems, and the recommended actions to take should such an error be encountered. Table 5-3 Serviceable Hardware Error Codes Table 5-3 Serviceable Hardware Error Codes 2. If this error persists, return monitor for service. NIBP Sensor Error. The two pressure transducers do not agree. 1. Check for blocked hoses in the pneumatic system. NIBP Pressure Violation Error. The pressure on the cuff could not be removed by normal means. A fault...

563 Buttons Knobs

Table 5-5 lists recommended actions to address problems with the knob and front-panel buttons. 1. The NPB-3900 fails to power-up when the ON STANDBY button is pressed. Take steps as noted in section 5.6.1. 2. The NPB-3900 powers-up, but some one of the other buttons does not respond. 1. Ensure that the keypad is plugged into the Main PCB. If the connection is good, change the keypad. 2. If the problem persists, change the Main PCB. 3. When the knob is rotated, no highlight appears on the...

564 Display Audible Tones

Table 5-6 lists recommended actions to address problems with the display and audible tones. Table 5-6 Display Audible Tones Problems Table 5-6 Display Audible Tones Problems 1. Adjust the LCD screen contrast by pressing the contrast button momentarily, then turning the knob four revolutions in each direction. Turning the knob clockwise should brighten the screen turning the knob counter- 2. Ensure that the backlight cable is connected 3. Ensure that the LCD connector is properly 4. If problem...

565 Operational Performance

Table 5-7 lists recommended actions to address problems related to operational performance. Table 5-7 Operational Performance Problems Table 5-7 Operational Performance Problems 1. The monitor appears to be operational, but the physiological values are suspect or nonexistent. 1. Replace each patient cable (or hose) with a known-good cable. 2. Ensure that the Patient Connector PCB is properly connected to the main PCB. Ensure that the hoses in the pneumatic system are properly connected, and...

56troubleshooting Guide

Problems with the NPB-3900 are separated into the categories indicated in Table 5-1. Refer to the paragraph indicated for further troubleshooting instructions. NOTE Taking the recommended actions discussed in this section will correct the majority of problems you may encounter. However, problems not covered here can be resolved by calling Nellcor Puritan Bennett Technical Services or your local representative. Powers down without apparent cause Monitor does not respond properly to buttons...

572Fault Evaluation

Table 5-8 provides fault indications and possible solutions. NPB-3900 gives error code 64 or 65, indicating communications problem w SpO2 module. Check 5-volt digital power supply. Check processor clock Y1. Check TXD buffer U5. NPB-3900 gives low-priority alarm, SpO2 Cable Sensor Disconnect Sensor may be disconnected or damaged. Patient Connector PCB may be defective. NPB-3900 gives status message SpO2 Pulse Search The sensor may be improperly applied to the patient or may be damaged. Try...

58 P3900 Troubleshooting Guide

Table 5-9 lists recommended actions to address printer problems. Table 5-9 P-3900 Troubleshooting Guide Table 5-9 P-3900 Troubleshooting Guide 1. With external power supply connected, the green EXTERNAL POWER indicator on the front panel is not lit. 1. Ensure that the external power supply input (PS-120 V or PS-240V) is plugged into an operational AC outlet of the appropriate voltage and frequency. 2. Disconnect the power supply output cable from the printer. Measure the voltage across pins 1...

62how To Use This Section

The step-by-step procedures that are used to access replaceable parts of the NPB-3900 are illustrated in the Disassembly Flow Charts in paragraphs 6.3, Figures 6-1, 6-2, 6-3 and 6-4. As indicated in the flow charts, the monitor consists of two main assemblies, the Front Case Assembly, and Rear Case Assembly. The Main PCB assembly is separable from the front case assembly. The circles on the flow charts contain reference designators that point to specific steps in the Disassembly Procedures. The...

65 Front Case Disassembly

Use a Phillips head screwdriver to unfasten the four corner screws and remove the display shield. The four screws also hold the LCD assembly in place. Remove the LCD Assembly, providing access to the Display Window. Remove Display Window by carefully prying up one corner, then peeling back. Remove the retaining spring clip. Remove the speaker. From the front, remove the knob by grasping the sides of the knob firmly and pulling straight back from the monitor. (The knob is friction fit on the...

66 Rear Case Disassembly

Procedure To remove a Rear Connector PCB Use a Phillips head screwdriver to remove the two screws holding the Rear Connector PCB to the rear cover. From outside the rear cover, use 3 16 socket driver to remove the two standoff fasteners of the RS-232 connector. From inside the rear cover, remove the Rear Connector PCB Assembly. Use Phillips head screwdriver to unfasten screw holding clamp to rear cover. Disconnect power lead from Rear Connector PCB. Remove Clamp and Pump. Procedure To remove...

67 Main Pcb Disassembly

To remove NIBP Pneumatic Assembly from the Main PCB Assembly Pull tubing from barbed fitting on rear of NIBP panel connector. Pull tubing from fittings on the pressure sensors and valve. To separate the Patient Connector PCB Assembly from the Main PCB Assembly Use wire cutters to remove the two Tinnerman fasteners securing the Patient Connector PCB Assy to the underside of the Main PCB. Disconnect the Patient Connector PCB Assy by pulling it straight up from the Main PCB. The battery fuse F301,...

81general Instructions

Failure to follow the instructions in this section may result in loss or damage to the monitor. If the original shipping carton is not available, use another suitable carton. North American customers may call Nellcor Puritan Bennett Technical Services to obtain a shipping carton. Prior to shipping the monitor, contact Nellcor Puritan Bennett's Technical Services Department or your local Nellcor Puritan Bennett representative for a returned goods authorization (RGA)...

83repacking In A Different Carton

If the original carton is not available, use the following procedure to pack the monitor 1. Place the monitor in a plastic bag. 2. Locate a corrugated cardboard shipping carton with at least 200 pounds per square inch (psi) bursting strength. 3. Fill the bottom of the carton with at least 2 inches of packing material. 4. Place the bagged unit on the layer of packing material and fill the box completely with packing material. 5. Seal the carton with packing tape. 6. Label the carton with the...

953 Temperature Measurement Display

Technique Range Accuracy Measurement Time 60 to 250 mmHg 30 to 235 mmHg 20 to 220 mmHg 40 to 200 BPM Mean error and standard deviation per ANSI AAMI SP10, 1992 Greater of 2 BPM or 2 of pulse rate value Meets performance standards of ANSI AAMI SP10-1992 Welch-Allyn SureTemp Thermistor Probe Oral - approximately 4 seconds Rectal - approximately 15 seconds

954 SpO2 Measurement Display

7G-1GG 2 digits G-69 Unspecified Accuracies are expressed as plus or minus X digits (saturation percentage points) between saturations of 70-100 . This variation equals plus or minus one standard deviation (1SD), which encompasses 68 of the population. All accuracy specifications are based on testing the subject monitor on healthy adult volunteers in induced hypoxia studies across the specified range. Adult accuracy is determined with Oxisensor II D-25 sensors. Accuracy for neonatal readings is...

A12 SpO2 A121 General

The NPB-3900 contains a saturated blood oxygen measurement system using pulse oximetry techniques for noninvasive monitoring. The SpO2 section is a separate minisystem with its own analog section, A D converter, and microprocessor. The SpO2 section resides in the isolated portion of the NPB-3900 and receives +5ISO and -5ISO DC power via transformer T201. This section communicates via RS-232 digital transfers through optical isolators U208 and U209. The SpO2 function is built...

A124 Preamplifier

NOTE In the following discussion, parts that are internal to the Oxichip circuit are noted with a U1. Prefix. The current-to-voltage (I-to-V) converter has a gain of -249K V A and a low-pass corner frequency of 30 kHz. The voltage amplifier has a gain of -2 V V and a low-pass corner frequency of 20 kHz. The voltage amplifier is disconnected from the I-to-V converter during LED switching transients to prevent transmission of the switching spikes into the Programmable Gain Amplifier (PGA). The...

A125 Programmable Gain Amplifier PGA Demodulator and Demultiplexer

The PGA (U1.A4) provides a variable gain to accommodate a wide range of signal strengths. As the PGA amplifies the signal from the preamp by a programmable gain, the demodulator shifts the frequency down to baseband, while the demultiplexer separates the IR and Red components of the signal. The PGA has a programmable gain from 1 to 128 in powers of 2. The PGA output goes to the peak detectors for status monitoring and to the demodulator demultiplexer (U1.A5, which is internal to the Oxichip...

A126 Filters and Level Shifter

The filters and level shifters are shown on the schematic sheet 2. The 10 Hz filters eliminate the high frequency components of the optical signal and get it ready for conversion to a digital signal, thereby smoothing out the Red and IR signal from the demutiplexer. The gain of the Red filter is eight, while the gain if the IR filter circuit is five. The Red filter circuit components consist of U1.A6-8, R19-21, R31, R34-37, C22, C29-30, and C37-38. The IR filter circuit components consist of...

A127 LED Driver

The LED driver circuit generates regulated and programmable currents for driving the sensor LEDs. The circuit switches the current in the proper phases of the LED strobe cycle. The IR and Red currents can be programmed independently. The LED currents are generated by forcing a programmable voltage across R9, then switching the resulting current through the LEDs. The LED driver is almost entirely contained within the Oxichip circuit. This driver also has an over-current detection feature that...

A131 General

The microcontroller is an Intel 386EX with a 16-bit data bus and a 24-bit address bus, of which we use 19 bits. There are eight control signals used, ADS , W R , D C , M IO , WR , RD , BLE , and BHE . The processor requests and receives instructions from the flash memory. The DRAM memory is used for storage of variables, etc. 16 BIT ADDRESS BUS RESET 40MHZ READY LCDCNTL LCDADJ CHRGST JP120 JP101 JP102 FLSHBSY SPKRU D RTCWR RTCDATA RTCCLK NPPVEN3 RTCCE PSOFF NPANPWR PROBEST...

A13215 Adcclk Adctx Adcrx

These signals are connected to the Synchronous Serial Unit within the processor and control the ADC in the NPB-3900. The processor's DMA1 channel initiates a DRAM memory transfer to the SSU and the 16-bit word is serially output to the ADC and the front-end. Each data bit on the ADCTX line is strobed into the ADC and the front end serial shift register on the leading edge of the ADCCLK signal. At the same time, the ADC puts out the previous conversion's data on the ADCRX line. This data is...

A13216 Uart Fpga Dram Flash Chip Selects

These signals are generated by the processor's Chip Select Unit and are generated each time the address space which corresponds to the signal is enabled. Only one of these signals can be true at a time and the software programs the address space for each of these signals. These signals are all low true. The DRAM is connected to CS6 and requires 1 wait state, the Flash is connected to UCS and requires one wait state, the FPGA is connected to CS3 and requires 0 wait states, and the UART is...

A141 General

The program for the NPB-3900 is stored in a 256K X 16 flash, U111. The flash is address-mapped in the upper 512k byte address space and requires one wait state (100ns) for reading or writing to the flash. Upon powering up, the processor requests and receives an instruction at location FFFFF0 hex, utilizing the address bus, signal UCS from the chip select unit within the processor, and the data bus. The executable flash is a word oriented flash, that is, reading and writing is done on a word...

A152 DRAM Timing

For the DRAM design we must generate 6 signals RAS , UCAS , LCAS , DRAMOE , DRAMWR , and CASADREN. All of these signals are generated in the FPGA from the 386EX signals, ADS , CS6 , M IO , D C , WR , and RD . Since the CSU is programmed for one wait state, the CSU generates the READY signal, which terminates the transfer.

A172 NPB3900 Connections to Printer

The RS-232 signal levels are defined in the following paragraphs. The RS-232 signal levels are defined in the following paragraphs. Signals are considered to be in the MARK (1) state when the voltage is more negative than - 3 volts with respect to ground. Signals are considered to be in the SPACE (0) state when the voltage is more positive than + 3 volts with respect to ground. For data signal lines, TX and Rex, the signal is considered to be in the binary 1 state when the voltage is more...

A18 Fpga Glue Logic

The Actel FPGA (U105) is a 3.3V, 4000 gate device which contains miscellaneous control and glue logic for the NPB-3900. It is packaged in a 100-pin TSOP. The register map for writing and reading follows. The FPGA contains the following control circuits. 7. TEMPERATURE PROBE HEATER PWM 10. A D CONVERTER SELECT control

A1810 Knob Detect

The rotating knob on the front of the unit has an optical interface. It is supplied with 5 volts and it and generates two signal channels (A and B) that are input to the FPGA on pins 93 and 94. When the knob rotates clockwise the square wave on CHANNEL A leads the square wave on CHANNEL B by 90 degrees. When rotating counterclockwise, CHANNEL B leads CHANNEL A by 90 degrees. This circuit exclusively ors the channels and generates an edge each time a channel input changes state. One flip flop is...

A1811 Ad Converter Select Control

The ADCS signal is used to reset and enable the ADC (U207, A D Converter). When powering up, the reset signal into the FPGA is ored into the ADCS signal or gate and goes high, then low when reset goes away. On the high to low transition the ADC resets itself and is ready for a new command. A programmable bit in the Control register, bit 7, can also be set by software to perform this function. When the ADC is commanded to take a conversion and EOC goes low, indicating the ADC is busy, the ADCS...

A183 Resetclock Phase Control

When power is turned on, a reset signal is entered on pin 64. The RESETFF is set true on the next CLK_40MHz rising clock edge and RESET exits on pin 47. This is the master reset signal for the whole board and the 386EX. At the same time, it is required to make sure that the control circuits are in sync with the 386EX, and this is done by generating our own phase 1 (CLK_PH1) and phase 2 (CLK_PH2) signals. CLK_PH1 starts as soon as RESET goes low. CLK_PH2 always follows CLK_PH1 and is the inverse...

A186 Pump Pwm Control

This circuit consists of an 8-bit holding registers and 8-bit up down counter, being clocked at 313 kHz. This circuit is used to control the NIBP pump by generating a pulse width modulated signal that drives the pump. The pump PWM signal exists on pin 3. The enable for this signal is the PWM_GO signal in the CONTROL register. The software loads a value into the 8-bit holding register. The counter is clocked by a 313 kHz clock. When the counter overflows, the value in the holding register is...

A187 Valve Pwm Control

This circuit consists of a 10-bit holding register and 10-bit up down counter, being clocked at 5MHz. This circuit is used to control the NIBP VSO valve by generating a pulse width modulated signal which drives the valve. The valve PWM signal exits on pin 74. The enable for this signal is the VALVE_GO signal in the CONTROL register. The software loads a value into the 10-bit holding register. The counter is clocked by a 5MHz clock. When the counter overflows, the value in the holding register...

A189 Speaker Frequency Generator

The speaker requires tones from about 300 Hz to 1 kHz with a 55 duty cycle. In order to give software full control over both the frequency and duty cycle, there are two software programmable 8-bit up counters, one for generating the low portion of the TONE_OUT and one for generating the high portion. The TONE_OUT flip flop is jammed reset when the FREQ_GO bit in the CONTROL REGISTER is low. This enables the SPEAKER LOW counter. The software programs the high and low values into the respective...

A2 Block Diagram

The Monitor (see Figure A-1) contains an isolated front-end section, powered by an isolated power supply, and in which the signals from SpO2, temperature, and ECG sensors are processed. The plastic tubing provides sufficient isolation for signals from the cuff in NIBP monitoring. A single A D converter is used to digitize processed temperature, NIBP, and ECG inputs the SpO2 module produces digitized data. A microcontroller, Intel 386, requests and receives instructions from a flash memory. The...

A33 Digital Transfers

Two digital optocouplers, U200 and U201, are used to transfer data and clock signals to the isolated front end. Serial shift register U66 receives the serial data, which is loaded into the register outputs when one shot U4 times out at the end of the clock burst. The eight bits thus loaded are The analog MUX channel (1 of 8) selector The ECG lead selector (3 valid combinations) Parity is forced by the host to ODD for each digital transfer. If EVEN parity is sensed, the analog channel will be...

A34 Linear Optical Coupler

The ECG and temperature measurements are transmitted from the floating section via a linear optical coupler (U202). The coupler has an LED and two matched photodiodes. One photodiode is used in a servo loop to control LED illumination. The second photodiode controls the output voltage on the other side of the isolation barrier. The two photodiodes are matched to produce a very linear result. The coupler has a raw gain of 1.000 with a tolerance of + 17.5 to -23.1 . All analog signals measured...

A35 Analog Multiplexer

The analog signals from the floating section are selected by a multiplexer (U67). The multiplexer selection is chosen by the digital byte loaded via the digital optocouplers. The eight available channels and their use as a parity check are shown in the following table. The table shows that three channels can be used for parity checking, the other channels may go to the positive limit during normal operation.

A4 Temperature Measurement Circuit A41 General

Patient temperature is measured using a thermistor probe. To speed up oral temperature measurements, the system controls a warmer in the probe tip and applies a predictive algorithm to the measurement process. The warmer is controlled to raise the probe temperature to 93 F (typically) before the probe is used by the patient. Typical oral temperature measurement time is 4 seconds. The probe warmer (a 30-ohm resistor in the probe assembly) is driven by a 100 kHz waveform through an isolation...

A43 Temperature Measurement Circuit

The first stage of the circuit is designed to produce an output signal (TEMP1, from U72A) that spans the voltage range of +4 to -4 volts as the thermistor covers the full temperature range. The output voltage is highest (+4) at 112 F, reaches zero at 93 F, and goes to -4V at 60 F. The second stage signal (TEMP2, from U72B) is a simple analog inverter. The A D conversion system reads the result from the first stage (TEMP1) while its output is positive, otherwise the result is...

A44 Temperature Probe Keying

The temperature probe has jumper keys that are used to code the various probes used with the system. Two pins of the probe's connector (J1) are open or shorted to ground to indicate the coding. A simple DAC is made using resistors to create a voltage indicative of the coding arrangement.

A53 Input ECG Signal First Gain Stage

The three input leads pass through analog multiplexers to differential amplifier U80. Weak pull-ups on the two leads insure that an open lead will be pulled up to +5V. The differential amplifier is configured for a gain of 4 with resistors R284 and R285. The junction of the two resistors is the center of the two input leads, and serves as a monitor for input common mode voltage. Buffer U75B drives (AC coupled) the shield of the input cable to effectively minimize input cable...

A55 ECG Second Gain Stage

The ECG signal is AC coupled to gain amplifier U73B, configured for a gain of 35. The low frequency RC cutoff frequency can be selected to use a 6.8 Meg ohm resistor (0.05 Hz), 750 K resistor (0.5 Hz), or a 1K resistor (340 Hz). The 1K resistor is used to rapidly reset the ECG front end during transient initial connections or in the event of other major signal disturbances. The 6.8 Meg resistor is the default selection with digital bits 0.5 Hz and ECGRES selecting the 750 K or 1...

A56 Pacemaker Detection

The ECG signal through the first two gain stages has an upper bandwidth of 1.8 kHz. This bandwidth is high enough to pass the rapid rise time, short width, pacemaker signal. Differentiator U73A is tailored to recognize this fast rise fall signal, and will trigger comparator U2, and one-shot U4B. The one-shot is set for a width of 8 msec and configured (with external blanking via D2) to be non-retriggerable. The width is enough to guarantee recognition by the system sampling rate while the...

A61 General

The NPB-3900 is turned ON and OFF by alternate button pushes of the front panel membrane switch. The button is sensed at U301 pin 3. U302 pin 3 produces a pulse for each button push which toggles U303 pin 1 between the ON and OFF state. A high level on U303 pin 4 resets the unit to the OFF state from U301 pin 4 when the battery is first connected to the unit, and from the ALARM signal if the unit operation stops because of watchdog time-out. The rising edge of the ON signal sets...

A62 Processor Watchdog

When the unit is powered up and running normally, it makes a pulse train gated by the watchdog timer called the WDT_PULSE signal. While this signal is present capacitor, C353 remains discharged. If something happens to the processor, the watchdog will time out. Regardless of which level the WDT_PULSE goes to, capacitor C353 will charge up in about 500 msec. The rising edge will clock the ALARM flip-flop (U304) and set the ALARM signal. The ALARM signal is reset when the battery...

A7 Audio Volume And Speaker Drive

The operational tones produced by the monitor produce the SPKRFREQ signal. This signal is volume controlled by U310, a digital potentiometer. The SPKRU D and SPKR_ADJ_PLS digital signals control the setting of the potentiometer. The attenuated waveform (from U310 pin 13) goes to the speaker drive amplifier U313, which connects to the speaker.

A82 General Buck Regulator Design

Several regulators in the NIBP3900 are buck-switching converter designs, a simplified diagram of which is shown in Figure A-8. In a buck converter (which provides a reduced, or bucked, output voltage), a series switch applies the input voltage to the output through an inductor. When the inductor current has built to a level sufficient to satisfy the load, the switch is opened. The current flowing in the inductor causes its input lead to fly down until it is caught by the catch diode at a...

A83 Battery Charger Power Supply

The transformer for mains isolation is external to the NPB-3900. The external unit provides an isolated 15 VRMS to the DIN connector on the back of the unit. This AC voltage is rectified by D318 and filtered to produce 16 to 25 VDC on C335. The battery charger is an integrated buck-switching regulator. The power switch is internal, the output inductor is L306, and the catch diode is D317. The regulator contains an accurate output current sense resistor located between pins 6 and...

A86 LCD Bias Power Supply

The LCD display requires a negative bias voltage (LCDBIAS) that adjusts the contrast of the display. The bias supply is thus an adjustable regulator, controlled by digital signals from the processor. The design is a modified buck regulator whereby the switch is Q307, the output inductor is L309, and the catch diode is D313. In the modified design, the output is taken from the bottom of the catch diode in order to produce a negative voltage. The output voltage is monitored by...

A87 Backlight Power Supply

The LCD display backlight is a cold cathode fluorescent light (CCFL), which requires a high voltage during normal operation. The starting voltage may be as high as 1000 VRMS, the running voltage is about 300 VRMS at 3 ma. This voltage is produced by a resonant Royer oscillator which produces a sinusoidal output waveform at about 50 kHz. The transistors Q305 and Q306 receive their base drive from the transformer. The output waveform is the result of the transformer inductance...

A92 Power

The NPB-3900 contains a pneumatic noninvasive blood pressure system. Mechanically the system consists of a pump, a proportional valve, and two pressure sensors. During a blood pressure reading, the system pumps up the cuff to a specific pressure then bleeds air slowly out while listening to the pressure for the heartbeat. The relative loudness of the heartbeat during the test is used to determine the systolic and diastolic pressure readings. See Figure A-15. The control and amplification...

A94 Pressure Sensors

Two redundant pressure sensors (PS201 and PS202) monitor the air pressure in the NIBP system. The sensors are powered from the NIBP +5VREG power and produce an output of 0-5 volts from pressures of 0-360 mm. Pressure sensor PS210 is used during the NIBP test. It is monitored directly by the system A D as an indicator of system pressure. The signal from PS1 is AC coupled and amplified by U216 to produce the OSC signal monitored by the system A D. The OSC signal represents the...

Alarms

Heart rate alarm, SpO2 alarm, (respiration rate alarm), systolic pressure alarm, diastolic pressure alarm, mean arterial pressure alarm, (temperature alarm), 0 corresponding vital sign was not in alarm state 1 corresponding vital sign was in alarm state NOTE In order to maintain a consistent trend data format between the NPB-3900 and NPB-4000 patient monitors, the NPB-3900 maintains a field for respiration rate alarm and temperature alarm, even though the NPB-3900 does not have an alarm for...

Chnl 2 Chnl 1 Chnl

TP3 Primary Input Preamplifier TP4 Secondary Input Preamplifier TP9 PGA output 5.7.3.2 Filter Outputs and ADC Input Waveform 5.7.3.2.1 SRC-2 Settings Figure 5-2 Filter Outputs and ADC Input Figure 5-2 Filter Outputs and ADC Input TP5 ADC Input TP6 Red Filter Output TP2 IR Filter Output

Diagnostic Menu

Error Codes System Information System A D Values NIBP Test The Diagnostic Menu lists the test and system-related information screens. Selection of an item in the menu will invoke that test or information screen. The test and information screens that appear in the Diagnostic Menu are as follows This screen displays the 10 most recent error code types, logged by the NPB-3900. After 10 error code types have been logged, the oldest error code type will be deleted as new error code types are added....

Dramoe

The DRAM requires 130 ns total time, read write and precharge for each cycle. There is one wait state for each DRAM access and a total of three T states which is 150 ns. Since the DRAM minimum access time is 130 ns, we have 20 ns of margin. We are using the Hitachi HM51W4260AL, which has a RAS time of 70 ns, a precharge time of 50 ns, a CAS time of 20 ns, and a WE time of 15 ns. The BLE and BLH signals are used to select byte-oriented reads and writes. There are 2 CAS lines, which are used to...

Nibp Test

Press NIBP to activate pump release to stop pump. Press Volume to open valve release to close valve. Press Alarm Silence to open proportional valve and deflate at 3 mmHg s release to close valve. Press Contrast to perform offset adjust. An NIBP Test screen is provided to facilitate troubleshooting problems and perform verification testing for the NIBP subsystem. Typically, when these tests are performed, the pneumatic system is connected to an external pressure- reading device and a closed...

Rowcol Addr Ucaslcas

Figure A-24 RAS and CAS Timing A-15.3 DRAM FPGA CIRCUITS The DRAM control circuits in the FPGA must decode the various 386EX control signals and generate the DRAM signals. This is done by using CS6 to set a flipflop when ADS and PH2 are true. When this is true, a flip-flop is set, which is output as RAS and is 75 ns long. This signal is generated for all DRAM accesses and refresh. The DRAM output is enabled when either BLE or BHE is true, which means a read is occurring. Since the DRAM outputs...

Switchposition

Power on the monitor and verify that the SpO2 and heart rate values are correctly displayed. Press the ALARM SILENCE button on the front panel of the monitor to temporarily silence the audible alarm. 2. Verify that the heart rate tone source, found in the Heart Rate Menu, is set to SpO2. Press the VOLUME button on the front panel of the monitor. Within 3 seconds of having pressed the button, rotate the knob CW and verify that the beeping heart rate tone sound level increases. 3. Rotate the knob...

23battery

If the NPB-3900 has not been used for a long period of time, the battery will need charging. To charge the battery, connect the NPB-3900 to an AC source as described in the Setup & Use section of the operator's manual. NOTE Storing the NBP-3900 for a long period without charging the battery may degrade the battery capacity. A complete battery recharge when not using the monitor requires 8 hours. The battery may be recharged while the monitor is in use in which case, the battery will require...

System Ad Values

This screen displays the current value of each analog-to-digital (A D) channel, in volts. Some of the channels are for AC-coupled signals (such as ECG input), so the numbers on the screen will be constantly changing when an input signal is present. These AC-coupled values indicate whether basic functionality of the channel is present, but no significance can be derived from the values of the numbers displayed. However, other A D channels read DC voltages, (for example, power supply voltages and...

Vitals

Heart rate, SpO2, (respiration rate), systolic pressure, diastolic pressure, mean arterial pressure, temperature, 4 characters leading zeroes suppressed right justified 4 characters leading zeroes suppressed right justified value will always be 0 right justified 4 characters leading zeroes suppressed right justified 4 characters leading zeroes suppressed right justified 4 characters leading zeroes suppressed right justified 4 characters, including decimal point leading zero not suppressed right...

64 Closed Case Disassembly

The paragraphs in this section describe and photographically illustrate procedures for disassembling the NPB-3900 to enable removal and replacement of suspected defective assemblies components. The sequence supports the guides in the previous paragraphs of this section. The illustrations may also contain juxtaposed photographs of the relevant spares. See Figure 6-1. If there is no apparent reason to replace the battery, begin with procedure B1. If the battery needs replacement, and there is no...

5622 Other Error Codes

If an error code occurs that is not listed in Section 5.6.2.1, take the following 1. Turn the monitor off, then on again. 2. If the error code still appears, take the monitor out of service and contact Nellcor Puritan Bennett Technical Services or your local Nellcor Puritan Bennett representative for advice on remedial action. 3. If the monitor powers up and the error code does not recur, enter the Diagnostic Mode and invoke the Error Code screen. Examine the record of the last 10 error codes...

75 Main Pcb Assembly

NIBP Pneumatic (Assembly) with Tubing, and Fittings Note The Main PCB for all of the NPB-3900 models has jumpers which must be set correctly so that the User Interface software is configured to support the measuring parameters of each particular model . There are two jumpers, marked JP101 and JP102, located immediately below the NIBP valve. Ensure that the jumpers are installed as noted in the table which follows Table 7-5 Main PCB Jumper Configuration Table 7-5 Main PCB Jumper Configuration

A42 Temperature Probe

The temperature sensor is an accurate thermistor in the probe whose resistance varies with temperature. The temperature circuit applies a constant voltage (0.4551 volts) to the thermistor at all times. The current through the thermistor varies with temperature based on its resistance value. The temperatures (including ambient and over temperature) to be measured by the NPB-3900 range from 16 C to 44.5 C (60.7 F to 112.1 F). The chart shows the probe resistance and corresponding current at room...

63disassembly Flow Charts

The charts have been developed for use with all models of the NPB-3900 family. Therefore, some disassembly procedures will not be applicable to model configurations of less than the full complement of functions. In most cases, the relevant subassemblies will not have been installed, and it will be apparent that the pertinent procedures will not apply. However, when a temperature-measuring function is involved, a different hardware configuration of the rear-case assembly is shown in the flow...

3343 Verification of Pneumatic System NPB3900

Tests in paragraphs 3.3.4.3.1 through 3.3.4.3.5 verify the functionality of the NPB-3900 pneumatic system. These tests were designed to use the Bio-Tek BP Pump noninvasive blood pressure simulator. The internal test volume of the Bio-Tek simulator is 250 cm, which is used to calculated the inflation deflation rate periods. The Bio-Tek simulator, or any equivalent NIBP simulator, is required to perform these tests. The NPB-3900 must be placed in Diagnostic Mode, with the NIBP Test screen active...

A123 Oxichip Circuit

At the heart of the SpO2 function is the Oxichip integrated circuit U1, which provides variable LED drive, photodetector amplification, variable gain, demodulation, filtering, and signal conditioning for the analog-to-digital converter ADC input. The Oxichip circuit generates its own LED modulation and photodetector demodulation timing. It requires a single clock at x, the desired LED switching frequency. A block diagram of the Oxichip is shown on sheet 2 of the schematic. The Oxichip circuit...

3342 Operation with an ECG Simulator NPB3930 NPB3940

With the monitor off, connect the ECG leads to the appropriate jacks on the ECG tester. 2. Connect the leads to the CE-10 ECG cable. Connect the CE-10 to the ECG input port on the NPB-3900. Set the ECG tester as follows NOTE The accuracy of the monitor's ECG measurements is 5 bpm. In the procedure below, add the tolerance of the simulator to the acceptable range of readings. 3. Press the ON STANDBY button to turn the monitor on. After the normal power-up sequence, verify the following...

Nellcor Puritan Bennett NPB3900 Patient Monitor

To contact Nellcor Puritan Bennett's representative In the United States, call I-8OO-NELLCOR or 510 463-4000 outside the United States, call your local Nellcor Puritan Bennett representative. Caution Federal law U. S. restricts this device to sale by or on the order of a physician. 0123 1998 Nellcor Puritan Bennett Inc. All Rights Reserved Nellcor Puritan Bennett Inc. 4280 Hacienda Drive Pleasanton, California 94588 U.S.A. Nellcor Puritan Bennett Inc. 2200 Faraday Avenue Carlsbad, California...