OMEGA 868F, 869C Manual

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TABLE OF CONTENTS

MODELS 868 AND 869 DIGITAL THERMOMETERS

SECTION PAGE

SECTION 1 INTRODUCTION ....................................................1

1.1 General Description....................................................................................................................1

1.2 Features................................................................................................................................................1

SECTION 2 INSTALLATION......................................................1

2.1 Unpacking ..........................................................................................................................................1

2.2 Battery Installation......................................................................................................................2

SECTION 3 OPERATION ........................................................2

3.1 Safety Precaution and Notes..............................................................................................2

3.2 Control and Display ..................................................................................................................2

3.3 Operating Procedure................................................................................................................3

3.4 Accuracy Considerations ....................................................................................................4

3.5 Three Wire and Four Wire Operations......................................................................4

SECTION 4 THEORY OF OPERATION......................................6

4.1 Three Wire Signal Conditioning ......................................................................................6

4.1.1 Zero Phase........................................................................................................................................6

4.1.2 Signal Phase ....................................................................................................................................7

4.2 Four Wire Signal Conditioning..........................................................................................9

4.2.1 Zero Phase........................................................................................................................................9

4.2.2 Signal Phase ..................................................................................................................................10

4.3 Analog-to-Digital (A/D) Converter ..............................................................................11

4.4 Polarity Detector..........................................................................................................................11

4.5 FET Drivers ........................................................................................................................................11

4.6 Low-Battery Detector ............................................................................................................12

SECTION 5 SERVICE INFORMATION......................................12

5.1 Disassembly ..................................................................................................................................12

5.2 Calibration ....................................................................................................................................14

5.3 Probe Compensation ..............................................................................................................16

5.4 Troubleshooting..........................................................................................................................16

5.4.1 Voltage Checks ..........................................................................................................................17

5.4.2 A/D Converter Checks ........................................................................................................17

5.4.3 Waveform Checks....................................................................................................................18

5.5 Static Sensitive Parts ..............................................................................................................19

5.6 Performance Verification ....................................................................................................19

SECTION 6 SPECIFICATIONS ................................................21

6.1 Parts List for Models 868 and 869 ..............................................................................24

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2.2 BATTERY INSTALLATION

A nine volt battery is supplied with the instrument but is not installed, to
avoid possible damage due to leakage during storage or shipment.
Install the battery as follows:

1. Remove the instrument back cover.

2. Insert the battery in place; make sure correct polarity is observed
and battery terminals are contacting the battery clips.

3. Install back cover.

SECTION 3 OPERATION

3.1 SAFETY PRECAUTION AND NOTES

WARNING

Do not subject the probe to a voltage more than 30 V
RMS, 42.4 V peak above earth ground, or a shock
hazard may result.

NOTE

Use only 100 ohm platinum RTD sensors that conform to the DIN
43760 standard (alpha = .00385). Other type sensors will give
inaccurate results. Maximum allowable lead resistance for
rated accuracy is 50 ohms per lead (four wire) or 10 ohms per
lead (three wire).

For best accuracy, it is recommended that the instruments be
used in the four wire configuration with a suitable four wire
probe. If three wire probes are used with the instrument in the
four wire mode, noisy readings will result (the displayed reading
will jump around).

3.2 CONTROL AND DISPLAY

Figure 3-1 shows the control layout and nomenclature. The following
paragraphs contain information on probe connection, three and four
wire selection, range selection, and basic temperature measuring
procedures.

NOTE

2

figure 3-2.

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SECTION 4 THEORY OF OPERATION

This section contains a brief description of operation that should
help a technician in understanding instrument operation during a
measurement, to aid in isolating possible malfunctions. Detailed
schematics of each model are provided at the end of the manual.

4.1 THREE WIRE SIGNAL CONDITIONING

Two phases are necessary to condition the signal for digitization.
Each of these phases has a period of one-half the A/D converter back
plane (BP) period. These two phases are called the zero phase and the
signal phase, respectively. During each phase, appropriate FETs are
switched on to configure the circuit as required.

4.1.1 Zero Phase

During the zero phase, certain FETs are switched on to configure the
circuit shown in Figure 4-1. This curcuit operates similarly to a sample­and-hold curcuit, in which voltage levels are capacitively stored for
later use. The following summarizes this function.

1. CRis connected across RR. The voltage charged on CRis
equal to IRR.

2. CZis connected across RZ+ L through LZ. The voltage charge
on CZis equal to I[RZ+ L].

Figure 4-1. Three Wire Zero Phase

6

3. The input of A1is connected to ground. The output of A1is
equal to [A1Vos].

4. CC is connected between the output of A1and common. The

voltage charged on CCis equal to the output voltage of A

or [A1Vos].

5. CAis connected between the output of the A2network and
common. The voltage charged on CAis equal to the output
voltage of A1attentuated by A2or [A1A2Vos].

4.1.2 Signal Phase

During the signal phase, the FET switching configuration changes so
that the voltages developed during the zero phase are connected to the
A/D converter. The configuration during the signal phase is shown in
Figure 4-2. The following discussion assumes that the circuit has gone
through more than one charge transformation:

1. CRis connected across CEand after a sufficient number of
zero and signal phases the voltage on CEapproaches that
stored on CR. That voltage is equal to IRR.

2. CZis connected between L2and the input of A1in a way that
opposes the voltage drop across RTand L4. Since the voltage
charged on CZis I(RZ+ L1) the voltage at the output of A1is

RZis made to equal the value of RTat 0°. This action elimi­nates the offset of RT(100Ω at 0°C).

3. CCis connected between the output of A1and the top of CDin
such a way that opposes the output of A1. The voltage
charged on CDis

If L4exactly equals L1then this reduces to A1I(RT-RZ).

1

[A1(I(RT+ L4) - I(RZ+ L2) + Vos]

or

[A1(I(RT- RZ+ L4- L1) + Vos]

A1(I(RT- RZ + L4 - L1) + Vos) -A1Vos

or

A1I(RT- RZ + L4 - L1)

4. CAis connected between the output of the A2network and the
top of CBin such a way that opposes the output of A2. The
voltage charged on CBis

A1A2(I(RT- RZ + L4 - L1) + Vos) -A1A2Vos

or

A1A2I(RT- RZ + L4 - L1)

If L4exactly equals L1then this reduces to A1A2I(RT- RZ)

7

.

4.2 FOUR WIRE SIGNAL CONDITIONING

There are two phases necessary to condition the signal for
digitization. Each phase lasts for a period equal to one-half of the
back plane period of the A/D converter. These are called the zero
and signal phase.

4.2.1 Zero Phase

During the zero phase, FETs are switched to configure the circuit
shown in Figure 4-3. The fourth wire adds an additional attenuation
that slightly increases the offset voltage at the input to amplifier A1.

1. CRis connected across RR. The voltage charged on CRis
equal to IRR.

2. CZis connected across RZ. The voltage charge in C
is equal to IRZ.

3. The input of A1is connected through L3. Since, ideally, zero
current flows into A1the voltage at the output of A1is equal
to [A1(IL4+ Vos)].

4. CC is connected between the output of A1and common. The
voltage charged on CCis equal to the output voltage of A
or [A1(IL4+ Vos)].

5. CAis connected between the output of the A2network and
common. The voltage charged on CAis equal to the output
voltage of A1attentuated by A2or [A1A2(IL4 + Vos)].

Z

1

Figure 4-3. Four Wire Zero Phase

9

4.2.2 Signal Phase

During the signal phase the 4 charged values of voltage are
transfered to other parts of the circuit (refer to simplified Figure 4-4).
The following explanations assume more than one charge transfer has
taken place.

1. CRis connected across CEand after a sufficient number of
zero and signal phases the voltage on CEapproaches that
stored on CR. That voltage is equal to IRR.

2. CZis connected between L2and the input of A1in a way that
opposes the voltage drop across RTand L4. Since the voltage
charged on CZis IRZthe voltage at the output of A1is

RZis made to equal the value of RTat 0°C. This action
eliminates the offset of RT(100Ω at 0°C).

3. CDis connected between the output of A1and the top of C
in such a way that opposes the output of A1. The voltage
charge on CDis

4. CAis connected between the output of the A2network and
the top of CBin such a way that opposes the output of A2.
The voltage charged on CBis

A1A2(I(RT - RZ + L4) + Vos) - A1A2(IL4+ Vos)

Due to this two phase measurement Vos and lead resistance
effects are eliminated.

[A1(I(RT + L4) - IRZ + Vos)]

or

A1(I(RT - RZ + L4) + IRZ + Vos)

D

A1(I(RT - RZ + L4) + Vos) - A1(IL4+ Vos)

or

A1I(RT - RZ)

or

A1A2I(RT - RZ)

Figure 4-4. Four Wire Signal Phase

10

4.6 LOW-BATTERY DETECTOR

Low-battery detection is accomplished by comparing the
regulated voltage between V+ and common to the output of the
voltage divider (R107 and R110), which is connected across the
battery. When the battery voltage decreases, the output of the
voltage divider rises above analog common, causing
comparator U103A to change state. This action enables the LO
BAT annunciator on the display.

SECTION 5 SERVICE INFORMATION

5.1 DISASSEMBLY

The instrument must be opened to replace the battery, to select
three or four wire operation, or for calibration. Troubleshooting
or parts replacement may require more complete disassembly
(see Figure 5-1). The sequence below describes the basic
procedure for disassembling the instrument.

1. Remove the back cover.

2. At this point, you obtain access to replace the battery, select
three wire or four wire operation, or perform calibration.
Replace cover.

3. To remove the PC board, unscrew the standoff securing the
board to the front case. The board may now be pulled free,
although the wires to the probe jack will still be attached.
When the board becomes free of the case, the switch cover
will pull free as well. If necessary, the board can be pulled
completely free by detaching the wires at the board end. The
probe jack may then be removed, if necessary, by removing
the nut securing it to the case and pushing the jack free from
the inside.

CAUTION

Handle the PC board only at the edges, whenever
possible, to avoid possible contamination, which could
degrade instrument performance.

4. The LCD assembly may be removed from the PC board by
carefully spreading the clips that secure the display to the
board. Once the assembly is free of the board, the various
parts will be loose, so handle the LCD with care.

12

CAUTION

Do not touch the elastomer contact strips or mating surfaces
on the PC board. Also, use care when spreading the clips to
avoid breaking them.

5. The instrument may be reassembled by reversing the above
prodcedure, using Figure 5-1 as a guide. When assembling
the instrument, take special note of the following points:

A. If the LCD was removed, be sure it is aligned properly

on the board, with the clips fitted properly into the
notch on each side of the board.

B. If the probe jack was disconnected, make certain the

wires are connected properly. The wire colors are
marked on the PC board.

C. Make sure the PC board is properly secured to the front

case with the standoff. The switch cover should be placed
on the switch when installing the PC board.

D. Once the rear cover is in place, secure it with the

attachment screws.

Figure 5-1. Exploded View

13

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Figure 5-2.

Connections for Performance Verification and Calibration

Table 5-1

Calibration

MODEL 868

CALIBRATION

ADJUSTMENT (°F) RESISTOR DESIRED

STEP POTENTIOMETER RANGE VALUE (Ω) READING

1 R104 200°F 93.03 Ω 00.0
2 R105 200°F 134.91 Ω 195.0
3 R103 1100°F 311.45 Ω 1100.0

MODEL 869

CALIBRATION

ADJUSTMENT (°C) RESISTOR DESIRED

STEP POTENTIOMETER RANGE VALUE (Ω) READING

1 R104 200°C 100.00 Ω 00.0
2 R105 200°C 174.00 Ω 195.0
3 R103 630°C 313.59 Ω 600.0

15

5.3 PROBE COMPENSATION

The procedure outlined in the last paragraph provides accurate
absolute instrument calibration, but it cannot compensate for
probe inaccuracy. Probe errors near 32°F (0°C) can be minimized
by using the following procedure.

1. Make up an ice water bath by firmly packing a dewar flask
or Thermos with pea-size ice cubes made of distilled water
and then filling the container with distilled water. Replace
melted ice with new ice while removing excess water during
the calibration procedure.

2. Connect the probe to be compensated to the instrument.

3. Drill a hole in the flask or Thermos cap just large enough to
accommodate the probe. Place the cap on the bath
container and pass the probe through the hole until the
probe tip rests at the center of the ice water bath.

4. Allow 20 minutes for the test fixture temperature to stabilize.
With the model 868 on the 200°F range, adjust R104 for a
reading of 32.0 on the display. For the Model 869, R104
should be adjusted for a reading of 00.0 with the instrument
on the 200°C range.

Using this method of probe calibration will uncalibrate the
instrument slightly when used with other probes.

5.4 TROUBLESHOOTING

The troubleshooting information, along with appropriate
schematics and parts lists, are included to serve as a guide to
enable equipment repair. The schematics and parts lists may vary
slightly from actual production units and are to be used as a guide
only. Likewise, the troubleshooting section is a guide only and
cannot cover all possible contingencies that may occur.

NOTE

Each Model 868 and 869 is covered by a 13 month warranty as
described on the inside front cover of this manual. Warranty will
be void if the unit shows evidence of having been tampered with.

To gain access to the PC board for troubleshooting, the rear
cover and internal shield must be removed, as described in the
disassembly instructions. When troubleshooting or replacing
components, handle the PC board only by the edges to avoid
possible contamination.

Recommended Equipment: Digital Multimeter (DMM) with 10
megohm input resistance, ±0.05% basic accuracy; triggered
sweep oscilloscope with dc to 10 MHz bandwidth.

16

5.4.1 Voltage Checks

Several voltage checks can be made simply by connecting a
DMM to various A/D converter IC pins. Table 5-2 summarizes
these voltage readings.

STEP ITEM/COMPONENT CONDITION COMMENTS

1 Connect DMM HI to +V Leave connected for

2 Connect DMM LO to >7.2 V dc Battery voltage

U102, pin 26 (-V)

3 Connect DMM LO to 5V ± 1 V dv Digital Common

U102, pin 37 (TEST)

4 Connect DMM LO to 3 V IN LO (COM)

U102, pin 30

5.4.2 A/D Converter Checks

TABLE 5-2

VOLTAGE CHECKS

REQUIRED

all voltage checks.

A/D converter operation can be checked by measuring the input
and reference voltages and then comparing the displayed reading
to a value calculated from these input voltages.

1. Connect a temperature probe to the instrument; make sure
the temperature remains stable while making voltage
measurements.

2. Connect the DMM LO terminal to analog common (pin 32 of
U102).

3. Connect the DMM HI terminal to pin 31 (IN HI) of U102 and
record the reading.

4. Connect the DMM HI terminal to pin 30 (IN LO) of U102
and record the reading.

5. Connect the DMM HI terminal to pin 35 (REF HI) of U102
and record the voltage.

6. Connect the DMM HI terminal to pin 36 (REF LO) and record
the reading

Using the measured values above, calculate the displayed
reading (neglecting the decimal point) as follows:

Display = 1000 (IN HI-IN LO)

(REF HI-REF LO)

If the displayed value does not agree with the calculated value to
within a few digits, the A/D converter is not functioning properly.

17

5.4.3 Waveform Checks

Several A/D converter waveform checks can be made using an
oscilloscope along with the information in Table 5-3.

1. Connect the oscilloscope LO input to analog common U102,
pin 32.

2. Connect the oscilloscope HI input to the A/D converter pin
indicated in the table.

3. Select an appropriate time base, input attenuator setting,
and trigger mode to stabilize the display.

4. Compare the displayed waveform with the corresponding
drawing in Table 5.3.

WAVEFORM CHECKS

TABLE 5-3

18

5.5 STATIC-SENSITIVE PARTS

MOS devices are designed to operate at very high impedance
levels. As a result, any normal static charge that builds up on
your person or clothing may be sufficient to destroy these
devices if they are not handled properly. Table 5-4 lists those
parts used in the Models 868 and 869 that might be destroyed
by static charge. When handling these devices, use the following
precautions:

1. Transport and handle these parts only in containers
designed to prevent static build-up. Typically, these parts will
be received in static-protected containers of plastic or foam.
Keep these devices in their original containers until ready for
installation.

2. Remove the devices from their protective containers only at a
properly grounded work station. Also ground yourself with a
suitable wrist strap.

3. Handle the devices only by the body; do not touch the
terminals or pins.

4. Any PC board into which the device is to be installed must
also be properly grounded.

5. Use only anti-static type solder suckers.

6. Use only grounded soldering irons.

7. Once the device is installed on the PC board, it is normally
adequately protected, and normal handling may resume.

CAUTION

This assembly contains electrostatic sensitive devices which
can be damaged by static discharge when touched. Observe
precaution when handling.

TABLE 5-4

STATIC-SENSITIVE PARTS

SCHEMATIC DESIGNATION

Q101, Q102, Q105-Q113, Q115, Q116,
U101, Q102, U103, U104

5.6 PERFORMANCE VERIFICATION

This performance verification procedure should be accomplished
after any parts replacement or circuit repair, or to check instrument
operation at any time incorrect operation is indicated.

19

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22

SPECIFICATIONS continued

MODEL 869

TEMPERATURE SENSOR TYPE:

Three wire or four wire 100 Ω
platinum RTD (alpha = .00385)

4 WIRE

ACCURACY*

SETTING RANGE RESOLUTION (18 °C TO 28 °C: 1 Year)

200 °C -100.0 °C to 199.9 °C 0.1

± 0.3 °C

-199.9 °C to -100.1 °C 0.1

± 1.5 °C

630 °C -100 °C to 630 °C 1

± 1 °C

-220 °C to -101 °C

1

±

2 °C

*ACCURACY:

Three wire accuracy is the same if contact
resistance errors are removed by calibration
of instrument plus probe at 0°C. Includes DIN
43760 (ITS-90) conformity, repeatability,
temperature coecient (18° to 28°C), time
stability (one year) and errors with up to 50 Ω
of lead resistance (each lead). Excludes probe
errors; however, probe errors around 0°C may
be compensated by an internal adjustment.

REPEATABILITY:

0.1 °C
ambient temperature.

TEMPERATURE COEFFICIENT:

18° to 28°C; included in
accuracy specication. From

-10° to 18°C, and 28° to
50°C: less than ±0.015°C/°C.

MAXI

MUM LEAD RESISTANCE:

(each lead):

Four wire: 50 Ω
Three wire: 10 Ω

SENSOR CURRENT: 500 µ A max.

MODELS 868 AND 869
GENERAL SPECIFICATIONS:

DISPLAY:

31/ 2

digit LCD, 0.5" (13 mm) height. Polarity and deci-

mal point indication

.

CONVERSION RATE:

1.5 readings per second.

OVERRANGE AND OPEN
SENSOR INDICATION:

Typical for one week at constant

PERFORMANCE VERIFICATION

RANGE °C VALUE (Ω) (18° to 28°C)

630°C 9.9 Ω -221 to -219
200°C 60.26 Ω -100.3 to -99.7
200°C 100.00 Ω -0.3 to +0.3
200°C 138.51 Ω 99.7 to 100.3
200°C 174.01 Ω 194.7 to 195.3
630°C 313.71 Ω 599 to 601

SECTION 6 SPECIFICATIONS

RESISTANCE ALLOWABLE READING

TEMPERATURE SENSOR TYPE:

SETTING RANGE RESOLUTION (18 °C TO 28 °C: 1 Year)

200 °F -100.0 °F to 199.9 °F 0.1

1100 °F -100 °F to 1100 °F 1

*ACCURACY:

-199.9 °F to -100.1°F 0.1

-360 °F to -101 °F 1

Three wire accuracy is the same if contact
resistance errors are removed by calibration
of instrument plus probe at 32°F. Includes DIN
43760 (ITS-90) conformity, repeatability,
temperature coecient (65° to 82°F), time
stability (one year) and errors with up to 50 Ω
of lead resistance (each lead). Excludes probe
errors; however, probe errors around 32°F may
be compensated by an internal adjustment.

TABLE 5-5

(continued)
MODEL 869

MODEL 868

Three wire or four wire 100 Ω
platinum RTD (alpha = .00385)

4 WIRE

ACCURACY*

± 0.4 °F

± 1 °F

2 °F

±

±

4 °F

REPEATABILITY: 0.2 °F Typical for one week at constant

ambient temperature.

TEMPERATURE COEFFICIENT: 65 °F to 82 °F; included in

MAXIMUM LEAD RESISTANCE:

(each lead): Four wire: 50 Ω

SENSOR CURRENT: 500 µ A max.

Three wire: 10 Ω

accuracy specication. From
14 °F to 65 °F, and 82 °F
to 122 °F: less than ±0.015 °F/°F.

21

SPECIFICATIONS continued

TEMPERATURE SENSOR TYPE:

SETTING RANGE RESOLUTION (18 °C TO 28 °C: 1 Year)

200 °C -100.0 °C to 199.9 °C 0.1

-199.9 °C to -100.1 °C 0.1

630 °C -100 °C to 630 °C 1

-220 °C to -101 °C

*ACCURACY:

Three wire accuracy is the same if contact
resistance errors are removed by calibration
of instrument plus probe at 0°C. Includes DIN
43760 (ITS-90) conformity, repeatability,
temperature coecient (18° to 28°C), time
stability (one year) and errors with up to 50 Ω
of lead resistance (each lead). Excludes probe
errors; however, probe errors around 0°C may
be compensated by an internal adjustment.

MODEL 869

Three wire or four wire 100 Ω
platinum RTD (alpha = .00385)

1

4 WIRE

ACCURACY*

± 0.3 °C
± 1.5 °C

± 1 °C

±

2 °C

REPEATABILITY:

TEMPERATURE COEFFICIENT:

MAXI

MUM LEAD RESISTANCE:

(each lead):

Four wire: 50 Ω
Three wire: 10 Ω

SENSOR CURRENT: 500 µ A max.

MODELS 868 AND 869
GENERAL SPECIFICATIONS:

DISPLAY:

CONVERSION RATE:

OVERRANGE AND OPEN
SENSOR INDICATION:

0.1 °C

Typical for one week at constant

ambient temperature.

18° to 28°C; included in
accuracy specication. From

-10° to 18°C, and 28° to
50°C: less than ±0.015°C/°C.

digit LCD, 0.5" (13 mm) height. Polarity and deci-

31/ 2
mal point indication

.

1.5 readings per second.

22

SPECIFICATIONS continued

MAXIMUM COMMON MODE
VOLTAGE:

COMMON MODE REJECTION
(Model 868):

42 V peak to earth.

Less than 0.001°F/volt at dc, 50 and 60 Hz
(100 Ω unbalance, LO driven).

COMMON MODE REJECTION
(Model 869):

Less than 0.001°C/volt at dc, 50 and 60 Hz
(100 Ω unbalance, LO driven).

ENVIRONMENTAL LIMITS FOR
OPERATING (Model 868):

14° to 122°F, less than 80% relative humidity
up to 95°F; linearly derate 1.5% RH/°F from
95° to 122°F.

ENVIRONMENTAL LIMITS FOR
OPERATING (Model 869):

-10° to 50°C, less than 80% relative humidity up to
35°C; linearly derates 3% RH/°C from 35° to 50°C.

ENVIRONMENTAL LIMITS FOR
STORAGE (Model 868):

-30° to 140°F, less than 90% relative humidity
up to 95°F; linearly derate 1.5% RH/°F from 95°
to 140°F.

ENVIRONMENTAL LIMITS FOR
STORAGE (Model 869):

-35° to 60°C, less than 90% relative humidity up to
35°C; linearly derate 3% RH/°C from 35° to 60°C.

RTD LINEARIZATION: Ratiometric dual-slope A/D with continuous

linearization.

INPUT CONNECTION: Four pin miniature instrumentation connector.

POWER: 9 V alkaline or carbon-zinc (NEDA 1604) battery

BATTERY LIFE, CONTINUOUS: 500 hours typical with alkaline battery; 300

hours typical with carbon-zinc battery.

BATTERY INDICATOR: Display indicates “LOBAT” when less than 10%

of life remains.

DIMENSIONS: H: 6.3” (160 mm) x W: 2.7” (69 mm) x D: 1.2”

(31 mm).

WEIGHT: Net weight 7.50 oz (210 gm).

CONSTRUCTION: Heavy duty ABS plastic housing.

23

6.1 PARTS LIST FOR MODELS 868 AND 869

SCHEMATIC DESCRIPTION SCHEMATIC

DESIG. LOCATION

BA101 Battery, 9 V, NEDA 1604 G1

C101 Capacitor, 0.1 F, 50 V, Ceramic Film E4

C102 Capacitor, 0.1 F, 50 V, Ceramic Film G1
C103 Capacitor, 0.1 F, 50 V, Ceramic Film F1
C104 Capacitor, 0.1 F, 50 V, Ceramic Film G1
C105 Capacitor, 0.22 F, 63 V, Metalized Polyester B1
C106 Capacitor, 0.047 F, 50 V, Metalized E3

Polypropylene
C107 Capacitor, 0.33 F, 63 V, Metalized Polyester E2
C108 Capacitor, 0.33 F, 63 V, Metalized Polyester F1
C109 Capacitor, 0.1 F, 63 V, Metalized Polyester D2

C110 Capacitor, 0.22 F, 63 V, Metalized Polyester D1

C111 Capacitor, 0.22 F, 63 V, Metalized Polyester E3
C112 Capacitor, 0.1 F, 63 V, Metalized Polyester E2
C113 Capacitor, 47pF, 500 V, Silver Mica or Ceramic E2
C114 Capacitor, 0.22 F, 63 V, Metalized Polyester E1
C115 Capacitor, 0.22 F, 63 V, Metalized Polyester B2

CR101 Diode, Silicon 1N4148 B1
DS101 Display, LCD H4

J1001 Connector, 4-tereminal Connector A3

(mates with J1001)
J1002 Connector, Battery G1
J1003 Connector, Battery G1
J1004 Connector, Pin A3
J1005 Connector, Pin A3
J1006 Connector, Pin A4
J1007 Connector, Pin A4

P1004 Terminal A3
P1005 Terminal A3
P1006 Terminal A4
P1007 Terminal A4

Q101 JFET, N-Channel B1
Q102 JFET, N-Channel B2
Q103 Transistor, NPN, Silicon, 2N3904 B4
Q104 Transistor, NPN, Silicon, 2N3904 B4
Q105 JFET, N-Channel C3
Q106 JFET, N-Channel C1
Q107 JFET, N-Channel E2
Q108 JFET, N-Channel D2
Q109 JFET, N-Channel E3

Q110 JFET, N-Channel B3

Q111 JFET, N-Channel C2
Q112 JFET, N-Channel C3
Q113 JFET, N-Channel E2

Q114 Transistor, NPN, Silicon, 2N3904 B4

24

Jumper strip

26

figure 3-2.

jumper

27

28

29

NOTES

30

WARRANTY/DISCLAIMER

OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and
workmanship for a period of 13 months from date of purchase. OMEGA Warranty adds an
additional one (1) month grace period to the normal one (1) year product warranty to cover
handling and shipping time. This ensures that OMEGA’s customers receive maximum
coverage on each product.

If the unit should malfunction, it must be returned to the factory for evaluation. OMEGA’s
Customer Service Department will issue an Authorized Return (AR) number immediately upon
phone or written request. Upon examination by OMEGA, if the unit is found to be defective it will
be repaired or replaced at no charge. OMEGA’s WARRANTY does not apply to defects resulting
from any action of the purchaser, including but not limited to mishandling, improper interfacing,
operation outside of design limits, improper repair, or unauthorized modification. This
WARRANTY is VOID if the unit shows evidence of having been tampered with or shows evidence
of being damaged as a result of excessive corrosion; or current, heat, moisture or vibration;
improper specification; misapplication; misuse or other operating conditions outside of
OMEGA’s control. Components which wear are not warranted, including but not limited to
contact points, fuses, and triacs.

OMEGA is pleased to offer suggestions on the use of its various products. However,
OMEGA neither assumes responsibility for any omissions or errors nor assumes liability
for any damages that result from the use of its products in accordance with information
provided by OMEGA, either verbal or written. OMEGA warrants only that the parts
manufactured by it will be as specified and free of defects. OMEGA MAKES NO OTHER
WARRANTIES OR REPRESENTATIONS OF ANY KIND WHATSOEVER, EXPRESSED OR
IMPLIED, EXCEPT THAT OF TITLE, AND ALL IMPLIED WARRANTIES INCLUDING ANY
WARRANTY OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
HEREBY DISCLAIMED. LIMITATION OF LIABILITY: The remedies of purchaser set forth
herein are exclusive and the total liability of OMEGA with respect to this order, whether
based on contract, warranty, negligence, indemnification, strict liability or otherwise, shall
not exceed the purchase price of the component upon which liability is based. In no event
shall OMEGA be liable for consequential, incidental or special damages.

CONDITIONS: Equipment sold by OMEGA is not intended to be used, nor shall it be used: (1) as
a “Basic Component” under 10 CFR 21 (NRC), used in or with any nuclear installation or activity;
or (2) in medical applications or used on humans. Should any Product(s) be used in or with any
nuclear installation or activity, medical application, used on humans, or misused in any way,
OMEGA assumes no responsibility as set forth in our basic WARRANTY/ DISCLAIMER language,
and additionally, purchaser will indemnify OMEGA and hold OMEGA harmless from any liability
or damage whatsoever arising out of the use of the Product(s) in such a manner.

RETURN REQUESTS / INQUIRIES

Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department.
BEFORE RETURNING ANY PRODUCT(S) TO OMEGA, PURCHASER MUST OBTAIN AN
AUTHORIZED RETURN (AR) NUMBER FROM OMEGA’S CUSTOMER SERVICE DEPARTMENT
(IN ORDER TO AVOID PROCESSING DELAYS). The assigned AR number should then be
marked on the outside of the return package and on any correspondence.

The purchaser is responsible for shipping charges, freight, insurance and proper packaging to
prevent breakage in transit.

FOR WARRANTY RETURNS, please have
the following information available BEFORE
contacting OMEGA:

1. P.O. number under which the product was
PURCHASED,

2. Model and serial number of the product
under warranty, and

3. Repair instructions and/or specific
problems relative to the product.

FOR NON-WARRANTY REPAIRS,

consult
OMEGA for current repair charges. Have the
following information available BEFORE
contacting OMEGA:

1. P.O. number to cover the COST

of the repair,

2. Model and serial number of product, and

3. Repair instructions and/or specific problems

relative to the product.

OMEGA’s policy is to make running changes, not model changes, whenever an improvement is possible.
This affords our customers the latest in technology and engineering.

OMEGA is a registered trademark of OMEGA ENGINEERING, INC.
© Copyright 1996 OMEGA ENGINEERING, INC. All rights reserved. This document may not be copied, photocopied,

reproduced, translated, or reduced to any electronic medium or machine-readable form, in whole or in part, without
prior written consent of OMEGA ENGINEERING, INC.

USA

MADE

IN

NOTES

31

MADE

IN

USA

OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and
workmanship for a period of 13 months from date of purchase. OMEGA Warranty adds an
additional one (1) month grace period to the normal one (1) year product warranty to cover
handling and shipping time. This ensures that OMEGA’s customers receive maximum
coverage on each product.

If the unit should malfunction, it must be returned to the factory for evaluation. OMEGA’s
Customer Service Department will issue an Authorized Return (AR) number immediately upon
phone or written request. Upon examination by OMEGA, if the unit is found to be defective it will
be repaired or replaced at no charge. OMEGA’s WARRANTY does not apply to defects resulting
from any action of the purchaser, including but not limited to mishandling, improper interfacing,
operation outside of design limits, improper repair, or unauthorized modification. This
WARRANTY is VOID if the unit shows evidence of having been tampered with or shows evidence
of being damaged as a result of excessive corrosion; or current, heat, moisture or vibration;
improper specification; misapplication; misuse or other operating conditions outside of
OMEGA’s control. Components which wear are not warranted, including but not limited to
contact points, fuses, and triacs.

OMEGA is pleased to offer suggestions on the use of its various products. However,
OMEGA neither assumes responsibility for any omissions or errors nor assumes liability
for any damages that result from the use of its products in accordance with information
provided by OMEGA, either verbal or written. OMEGA warrants only that the parts
manufactured by it will be as specified and free of defects. OMEGA MAKES NO OTHER
WARRANTIES OR REPRESENTATIONS OF ANY KIND WHATSOEVER, EXPRESSED OR
IMPLIED, EXCEPT THAT OF TITLE, AND ALL IMPLIED WARRANTIES INCLUDING ANY
WARRANTY OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
HEREBY DISCLAIMED. LIMITATION OF LIABILITY: The remedies of purchaser set forth
herein are exclusive and the total liability of OMEGA with respect to this order, whether
based on contract, warranty, negligence, indemnification, strict liability or otherwise, shall
not exceed the purchase price of the component upon which liability is based. In no event
shall OMEGA be liable for consequential, incidental or special damages.

CONDITIONS: Equipment sold by OMEGA is not intended to be used, nor shall it be used: (1) as
a “Basic Component” under 10 CFR 21 (NRC), used in or with any nuclear installation or activity;
or (2) in medical applications or used on humans. Should any Product(s) be used in or with any
nuclear installation or activity, medical application, used on humans, or misused in any way,
OMEGA assumes no responsibility as set forth in our basic WARRANTY/ DISCLAIMER language,
and additionally, purchaser will indemnify OMEGA and hold OMEGA harmless from any liability
or damage whatsoever arising out of the use of the Product(s) in such a manner.

WARRANTY/DISCLAIMER

RETURN REQUESTS / INQUIRIES

Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department.
BEFORE RETURNING ANY PRODUCT(S) TO OMEGA, PURCHASER MUST OBTAIN AN
AUTHORIZED RETURN (AR) NUMBER FROM OMEGA’S CUSTOMER SERVICE DEPARTMENT
(IN ORDER TO AVOID PROCESSING DELAYS). The assigned AR number should then be
marked on the outside of the return package and on any correspondence.

The purchaser is responsible for shipping charges, freight, insurance and proper packaging to
prevent breakage in transit.

FOR WARRANTY
the following information available BEFORE
contacting OMEGA:

1. P.O. number under which the product was
PURCHASED,

2. Model and serial number of the product
under warranty, and

3. Repair instructions and/or specific
problems relative to the product.

OMEGA’s policy is to make running changes, not model changes, whenever an improvement is possible.
This affords our customers the latest in technology and engineering.

OMEGA is a registered trademark of OMEGA ENGINEERING, INC.
© Copyright 1996 OMEGA ENGINEERING, INC. All rights reserved. This document may not be copied, photocopied,

reproduced, translated, or reduced to any electronic medium or machine-readable form, in whole or in part, without
prior written consent of OMEGA ENGINEERING, INC.

RETURNS, please have

FOR NON-WARRANTY REPAIRS,

consult
OMEGA for current repair charges. Have the
following information available BEFORE
contacting OMEGA:

1. P.O. number to cover the COST

of the repair,

2. Model and serial number of product, and

3. Repair instructions and/or specific problems

relative to the product.

0315