Welch Allyn SureTemp 767 User manual
SureTemp
Thermo Menu
Operation Manual
®
Model 767 Thermometer
Technical Manual
Technical Manual
© 1997 by Diatek Instruments, Inc., A Welch Allyn Company. All rights reserved. No part of this manual may be reproduced
or transmitted in any form or by any means, electronic or mechanical, including photocopy, without prior consent in writing
from Welch Allyn. Printed in the USA
SureTemp is a trademark of Welch Allyn, Inc. All rights reserved.
Technical Manual
TABLE OF CONTENTS
WARRANTY.......................................................................................................................................... 1
SPECIFICATIONS................................................................................................................................. 2
OPERATIONAL CHARACTERISTICS................................................................................................... 2
Introduction ...................................................................................................................................... 2
Basic System Description................................................................................................................. 2
Safety & Warnings ........................................................................................................................... 4
Setup................................................................................................................................................ 4
Changing Probes.............................................................................................................................. 5
Normal Mode.................................................................................................................................... 5
Monitor Mode ................................................................................................................................... 5
Biotech Mode ................................................................................................................................... 5
PREVENTATIVE MAINTENANCE......................................................................................................... 6
Cleaning and Sterilization................................................................................................................. 7
Routine Cleaning................................................................................................................................. 7
ETO Gas Sterilization Procedure......................................................................................................... 7
CALIBRATION TESTING...................................................................................................................... 7
Calibration Key Procedure................................................................................................................ 7
M9600 Procedure............................................................................................................................. 8
THEORY OF OPERATION.................................................................................................................... 8
Technical Overview.......................................................................................................................... 8
Probe Enhancements....................................................................................................................... 8
Probe Switch.................................................................................................................................... 9
Monitor Mode ................................................................................................................................. 10
Normal Mode.................................................................................................................................. 11
Power Supply................................................................................................................................. 11
Microcontroller I/O Assignments..................................................................................................... 12
Memory/IO Input/Output Assignments............................................................................................ 13
IIC Interface to LCD Display Driver................................................................................................. 14
Reset/Self Tests............................................................................................................................. 15
Microprocessor Clock..................................................................................................................... 16
Temperature Measurement and Display......................................................................................... 16
A/D Power Control.......................................................................................................................... 17
Probe Detection.............................................................................................................................. 17
Probe Warming.............................................................................................................................. 17
Liquid Crystal Display..................................................................................................................... 18
i
Welch Allyn Model 767T
Backlight (Optional)........................................................................................................................ 18
Horn 19
F/C Switching................................................................................................................................. 19
ERROR CODES.................................................................................................................................. 19
TROUBLESHOOTING......................................................................................................................... 21
Equipment Required....................................................................................................................... 21
Terminology ................................................................................................................................... 22
Troubleshooting Table.................................................................................................................... 23
FIELD SERVICEABLE REPAIRS........................................................................................................ 28
FIELD SERVICEABLE PARTS............................................................................................................ 29
THERMOMETER DISASSEMBLY....................................................................................................... 29
THERMOMETER REASSEMBLY........................................................................................................ 34
SUGGESTED SPARE PARTS LIST.................................................................................................... 35
OPTIONS AND ACCESSORIES .........................................................................................................35
TABLE OF FIGURES
FIGURE 1 - THERMOMETER DIAGRAM.............................................................................................. 3
FIGURE 2 - SYSTEM BLOCK DIAGRAM............................................................................................ 10
FIGURE 3 - LCD DISPLAY.................................................................................................................. 15
FIGURE 4 - THERMOMETER ASSEMBLY DRAWING....................................................................... 30
FIGURE 5 - SYSTEM SCHEMATIC .................................................................................................... 32
FIGURE 6 - PRINTED CIRCUIT ASSEMBLY...................................................................................... 33
ii
Technical Manual
WARRANTY
3-YEAR LIMITED WARRANTY ON NEW INSTRUMENTS
Welch Allyn, Inc. (Welch Allyn) is warranted to be free from original defects in material and
workmanship under normal use and service for a period of three years fr om the date of first shipment
from Welch Allyn. This warranty shall be fulfilled by Welch Allyn or its authorized representative
repairing or replacing at Diatek's discretion, any such defect, free of charge for parts and labor.
Welch Allyn should be notified via telephone of any defective product and the item should be
immediately returned, securely packaged and postage prepaid to Welch Allyn. Loss or damage in
shipment shall be at purchaser's risk.
Welch Allyn will not be responsible for loss associated with the use of any Welch Allyn product that ( 1)
has had the serial number defaced, (2) has been repaired by anyone other than an authorized Welch
Allyn Service Representative, (3) has been altered, or (4) has been used in a manner other than in
accordance with instructions.
: Instrumentation purchased new from
90 DAY LIMITED WARRANTY ON PROBES AND PROBE COVERS
Welch Allyn warrants probe covers and probes to meet W elch Allyn’s specifications f or the Product at
the time of purchase and to be free f rom original defects in material and workm anship under normal
use and service for a period equal to 90 days from the date of first shipment of such Product to the
customer by or on behalf of Distributor.
THIS WARRANTY IS EXCLUSIVE AND IN LIEU OF ANY IMPLIED WARRANTY OR
MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE, OR OTHER WARRANTY OF
QUALITY, W HETHER EXPRESSED OR IMPLIED. WELCH ALLYN W ILL NOT BE LIABLE FOR ANY
INCIDENTAL OR CONSEQUENTIAL DAMAGES.
The information in this manual has been car efully reviewed and is believed to be accurate; however,
no responsibility is assumed for inaccuracies. Further more, this information does not convey to the
purchaser of Welch Allyn devices any license under the patent rights to the manufacturer.
:
1
Welch Allyn Model 767T
SPECIFICATIONS
Case Dimensions: 5.1 inches high x 4.1 inches wide x 4.0 inches deep.
Case Material: ABS Plastic.
Weight: 1.0 lbs
Input: Welch Allyn Thermistor Probe (Oral P/N 02767-000, Rectal P/N 02767-100).
Display range:
Laboratory Accuracy:
Clinical Accuracy: Meets the proposed ASTM clinical test criteria.
Push buttons: Mode button
Probes: Interchangeable Oral, Rectal
Power Source: Model 767 Wall Transformer.
Display Type: Liquid Crystal Display, 3½ digits plus special icons.
Operating temperature:
Storage Temperature:
28.9o C to 42.2o C (84.0o F to 108.0o F).
± 0.2o F in the Monitor mode and in a water bath per Welch Allyn SOP 90565-000.
16o C to 40o C (60.8 o F-104o F) @ 15% to 95% RH non-condensing per ASTM E1112-86.
-20o C to 50o C (-4o F-120o F) @ 15% to 95% RH non-condensing per ASTM E1112-86.
OPERATIONAL CHARACTERISTICS
Introduction
The Welch Allyn 767 SureT emp is a wall mounted thermistor thermomet er to be used f or measuring
patient temperatures rang ing f rom 84 °F to 108 ° F (28.9 °C to 42. 2 °C). Or al and r ectal probes utilize
single-use disposable probe covers which limit cross-contamination. Or al and r ectal tem peratur es ar e
taken using Normal or Monitor operat ing modes. Axillary temperatures are taken with an oral probe
with the unit operating in the Monitor mode. In the
Normal
mode, the thermometer’s microprocessor
“predicts” body temperature in about 4 seconds for oral temperatures and in about 15 seconds for
rectal temperatures. The
Monitor
mode continuously displays the temperature of the pr obe which will
reflect the patient’s actual tem perature in about 3 minutes and will continue for as long as the probe
remains in place.
Basic System Description
The thermometer system consists of four main components: the external AC power supply, the
thermometer instrument, the probe, and the probe cover.
The M767T Thermometer can use either a Welch Allyn Model 767 domestic (120V 60HZ) or
international (230V 50Hz) Wall Transformer or a Welch Allyn Model 77305 AC Adapter for its external
AC power supply. These power supplies are available from Welch Allyn.
The main instrument’s operation is described below.
The Model 767T is easily connected to the Model 767 Wall Transformer. Two screws are used to
secure the Model 767T to the Model 767 Wall Transformer. The use of a 9’ long probe cord with a
safety latch incorporated into its connector housing ensures that the Model 767T can be safely used
with the Model 767 Wall Transformer without slipping out of its connector.
2
Technical Manual
The Model 767T probe is similar in appearance to the probe for the M600, M670, and M675; but is
incompatible with any of these instruments. M600, M670, and M675 probe are also incompatible with
the Model 767T instrument.
Welch Allyn’s 767T thermistor based probes can be identified by color combinations as follows:
Handle
Color
Fog White Blue Fog White,
Top Color Connector
Color/Type
Model # Probe Type
M767T Oral
Latching
Fog White Red Fog White,
M767T Rectal
Latching
The Model 767T instrument’s connector receptacle configuration and size disallows insertion of any
but Model 767T probes.
The probe covers are unchanged from previous models and are compatible for use with all of Welch
Allyn’s thermistor based thermometers.
9
E
D
O
M
1
7
8
2
3
4
1. Display 6. Probe
2. Probe storage channel 7. Probe handle collar
3. Dual probe cover storage well 8. Ejection button
4. Probe connector receptacle 9. Mode selection button
5. Probe connector receptacle latch
6
5
FIGURE 1 - THERMOMETER DIAGRAM
3
Welch Allyn Model 767T
Safety & Warnings
CAUTION: DISCONNECT THE SYSTEM FROM THE MAINS SUPPLY BEFORE CONNECTING
THE 767 SURETEMP 4 THERMOMETER.
USE THE 767 SURETEMP 4 WITH WELCH ALLYN 3.5V 767 SERIES WALL TRANSFORMER
ONLY.
DO NOT USE IN THE PRESENCE OF FLAMMABLE ANESTHETICS.
Caution: Federal (USA) law restricts this device to sale by or on the order of a physician.
In order to obtain accurate and reliable temperature-taking results and ensure patient safety, it is
important that this booklet be read thoroughly prior to using the instrument. If you have any technical
or clinical questions concerning the thermometer’s use and/or care, please contact our Customer
Service Department at (800) 854-2904.
• Single-use disposable probe covers, available from Welch Allyn or Diatek, will limit patient cross-
contamination. The use of any other probe cover or the failure to use a probe cover may produce
temperature errors and will invalidate the instrument’s warranty.
• Oral probes (blue ejection button) are to be used for taking oral and axillary temperatures only.
Rectal probes (red ejection button) are to be used for taking rectal temperatures only. The use of
the wrong probe will produce temperature errors.
• The thermometer case is not waterproof; do not drip fluids onto it.
• Do not use this instrument for any purpose other than that specified in this booklet. Doing so will
invalidate the instrument’s warranty.
• Do not use the thermometer if you notice any signs of damage to the probe or instrument.
Contact our Customer Service Department for immediate assistance.
Setup
1. Install supplied Oral probe or optional Rectal probe by inserting the latching plug on the end of
the coiled cord into plug receptacle on the unit. The plug snaps into place and cannot be
removed without depressing the latch. (Figure 1).
2. Insert probe shaft completely into probe storage channel.
3. Turn on the 767 Wall Transformer.
4.
displayed, the thermometer is characterizing the probe. The display will clear when complete.
This process will take from 10 - 70 seconds.
5. Remove the probe from the storage channel.
(blinks) and (steady) are displayed when an oral probe is installed. When
is displayed when a rectal probe is installed.
6. Observe the LCD to see that all display segments appear followed by the display of the probe
type OrL = Oral or rEC = Rectal. Replace probe in storage channel.
7. Insert two boxes of disposable probe covers (part number 05031) into the dual storage well.
4
Technical Manual
Changing Probes
• Depress the latch and unplug the probe connector from the thermometer.
• Remove the probe from the storage channel.
• Repeat steps 1 through 6 in the SETUP section.
Normal Mode
Most temperatures are taken in the Normal (predictive) mode. The thermometer automatically resets
to the Normal mode after the probe is returned to the storage channel.
Note:
For Oral probes; if the instrument’s display changes to the probe type display,
the probe cover is loaded, the display will change to°F (without
cover. The instrument is not ready for the probe to be inserted into the patient’s mouth until the
display returns to
The thermometer will switch to Monitor Mode automatically under the following conditions:
1. If the prediction algorithm has not been activated within 30 seconds of withdrawing the probe
from the probe storage channel.
2. If the instrument determines that room temperature is above 33.9°C (93.0°F).
The thermometer reads the probe temperature immediately upon removal of the probe’s shaft
from the storage channel. If the probe is extracted immediately after taking a temperature; it will
not have had sufficient time to cool to room temperature. This will cause the instrument to detect
a false room temperature higher than actual room temperature.
OrL°F
.
OrL
) briefly upon loading of the probe
OrL°F
, before
Monitor Mode
Monitor mode is generally used for long term temperature monitoring, taking axillary temperatures, or
when difficult situations prevent accurate temperatures from being taken in the Normal mode.
When used correctly, the instrument will display the patient’s temperature in about 4 seconds. The
instrument will beep briefly to signal completion of the Normal mode temperature cycle.
If the probe’s shaft is not inserted into the storage channel within 30 seconds of completion of a
Normal mode temperature cycle, the instrument will shut off. Simply replace the probe’s shaft into the
storage channel to prepare for the next temperature.
Note:
The instrument will shut off automatically if the probe temperature remains below 28.9°C
(84.0°F) for more than 5 minutes.
Biotech Mode
Biotech mode provides the ability to query the following information:
1. Display test.
2. Software revision.
3. Internal temperature reference measurement to the nearest 1/100 of a degree Fahrenheit.
5
Welch Allyn Model 767T
4. Probe temperature to the nearest 1/100 of a degree Fahrenheit (98.30 will be displayed as 830).
Biotech Mode is entered by the following steps:
Note: While in the Biotech mode, the leading digit and decimal point are suppressed in order for the
instrument to display temperatures at higher resolution (i.e., 98.3 °F will be displayed as 830).
1. Ensure that a probe has been installed.
2. Depress and hold the Mode button for 7 seconds.
3. Observe that the instrument completes its display test. This is the same display test as initiated
when power is first applied. Each segment of the display is individually lit. Following this, all
segments are lit briefly.
4. The instrument will then momentarily display the software revision with the left half of the probe
shaft icon and the probe cover icon (indicating Biotech Mode). The display should show “r X.X”
where “X.X” is the revision number (i.e., r1.5). You will need to know the revision number when
discussing operation with Welch Allyn customer support.
5. A temperature display of the internal-reference-resistor measurement comes next. This reading is
generated by the instrument reading an internal, precision, fixed resistor as if it were a probe. If all
of the A/D conversion electronics are functioning properly, this measurement will produce a
reading between 678°C (36.78°C) and 689°C (36.89°C), or 820°F (98.20°F) and 840°F (98.40°F),
inclusive. Momentarily depressing the Mode button will always toggle the reading between Celsius
and Fahrenheit regardless of the mode.
6. A display of the probe tip temperature can now be obtained by withdrawing the probe from its
holder. The display will be of the same form as the internal-reference-resistor measurement
display (see above).
Note: If the probe is not removed from the probe holder within 1 minute, the unit will exit from the
Biotech Mode.
7. To exit Biotech Mode at any time, put the probe back into its holder. If the probe was never
removed from its holder, pull it out from its holder and then return it to its holder.
If you cannot enter the Biotech mode, refer to the
Troubleshooting
section.
Biotech Mode Problems
section of the
PREVENTATIVE MAINTENANCE
The following suggested preventative maintenance is recommended to maximize uninterrupted
service on the Model 767 SureTemp 4 Thermometer
Units which are in service on a regular basis should have the following preventative maintenance
performed every 6 months:
1. Visually inspect the thermometer for physical damage which might cause future product failure.
2. Clean the unit per instructions in your Directions for Use manual supplied with the thermometer
and/or per the instructions below.
6
Technical Manual
3. Perform the power up display test, startup display test and Model 9600 Calibration Testing
procedure found in the Model 9600 Operation Manual. Perform calibration adjustment if
determined necessary by following the procedure in this manual.
Cleaning and Sterilization
Routine Cleaning
Refer to the Directions for Use for routine cleaning
ETO Gas Sterilization Procedure
When no other form of decontamination such as a germicidal wipe is acceptable, a low temperature,
(not to exceed 48.9°C (120°F)) ETO gas sterilization cycle may be used. Refer to your institution’s
standard operating procedure for the length of the cycle.
This type of sterilization may cause some hazing of glossy plastic surfaces and should be used only
when absolutely necessary.
1. Disconnect the Model 767 Thermometer from the power supply.
2. Ensure that the probe is removed from its storage channel and disconnected from the instrument.
3. Remove any probe covers from the probe cover storage well
4. Wrap the thermometer in a standard sterilization type packaging such as a Baxter Tower Dualpeel
Sterilization Pouch.
5. ETO gas sterilize at a temperature not to exceed 48.9°C (120°F) and aerate.
6. Remove the sterilization packaging.
7. Before applying power, allow the probe and instrument to stabilize to room temperature for
at least
one hour.
8. Verify proper calibration of the thermometer and probe using the Welch Allyn Model 9600
Calibration Tester.
CALIBRATION TESTING
Calibration Key Procedure
Unplug the probe from the thermometer. Insert the Calibration Key into the probe connector
receptacle on the thermometer. Remove the probe shaft from the probe storage channel to initiate a
temperature taking cycle. Wait for the display test and then observe the display. The display must
read between 97.1°F and 97.5°F inclusive for the calibration of the instrument to be correct. Remove
the Calibration Key and reinstall the probe connector plug. Then install the probe into the probe
storage channel. (This will initiate a probe characterization cycle.)
Note:
This Cal Key test does not test the calibration of the probe. To do so requires the use of the
Welch Allyn Model 9600 Calibration Tester.
7
Welch Allyn Model 767T
If the reading from the Cal Key is not within the specified range or you are having other problems with
the use of the Cal Key, refer to the
Cal Key Problems
section of the
Troubleshooting
section.
M9600 Procedure
The M9600 Calibration Tester provides a convenient means of testing the entire thermometer system
(instrument and probe). The 9600 must be warmed up and stable at one of the two available
temperature settings. The thermistor based instrument under test must be in Monitor mode and no
probe cover loaded. The probe is inserted into the small hole in the dry heat well of the 9600 and
allowed to settle to the final temperature. The reading on the thermometer must be within the range
specified on the 9600. Refer to the M9600 Operation Manual for complete instructions.
Note:
All Welch Allyn thermometers (thermistor and infrared ear thermometers can be checked in the
M9600.)
If you are having problems with the use of the M9600, refer to the Troubleshooting section in the
M9600 Operation Manual.
THEORY OF OPERATION
Technical Overview
The heart of the Model 767 Thermometer is comprised of two custom integrated circuits, a standard
microcontroller, and an LCD driver which provide most of the microprocessor and analog circuit
functions. All control functions are governed by the Motorola MC68HC11D0 microcontroller (U1) and
a memory/IO chip (U2). All analog interfacing to the microprocessor, probe, horn, self-calibration
circuit, and backlight is provided by U4, and the LCD is controlled by U5.
Probe resistance measurements are made by measuring pulse widths which are generated by
sequentially switching in two calibration resistors and the probe thermistor, one at a time. These pulse
widths are measured by the microcontroller which calculates the probe resistance. The actual probe
temperature is then calculated from the probe resistance.
Probe Enhancements
The Model 767 Thermometer has the capability to detect probe type - Oral vs. Rectal. This allows the
oral temperatures to be as fast as possible (4 seconds) by using different operating modes based on
probe type. Rectal probes give a Normal mode temperature in about 15 seconds. Probe type
recognition also allows the use of minor differences in prediction parameters tailored to the
temperature taking site to help increase speed over most previous products.
The probe type is configured for thermometer recognition by connecting the appropriate combination
of probe connector contacts to ground within the probe assembly connector.
In addition to the probe type enhancements, Model 767 Thermometer probes have been improved for
thermal time constant (speed of response).
Model 767 Thermometer Oral probes incorporate a warming resistor in the tip to pre-warm the probe
before placement in the mouth thus speeding response even further.
8
Loading...