Vanguard Instruments II Series User manual

OPERATING INSTRUCTIONS
for the
MODEL ATO-250™
10-250 Amperes
Digital Micro-Ohm Meter
Series II
ID Number VIC-25000-S2
Vanguard Instruments Company
1710 Grevillea Court
Ontario, California 91761
TEL: [phone] JULY 2001
FAX: [phone] Rev 0

ATO-250™ Operating Procedures
ii
SAFETY SUMMARY
This device shall be used only by trained operators.
All devices under test shall be off line and fully isolated.
Do Not Service or Test Alone
Do not perform test procedures or service unless another person is also present who is capable of
rendering aid and resuscitation.
Do Not Modify Test Equipment
Do not install substitute parts or perform any unauthorized modification to any Model ATO-250
test unit, due to the added risk of introducing additional or unknown hazards. To ensure that all
designed safety features are maintained, it is recommended that repairs be performed only by
Vanguard Instruments Company factory personnel or by an authorized repair service.
Unauthorized modifications can cause serious safety hazards and will nullify the manufacturer's
warranty.
Follow Exact Operating Procedures
Any deviation from procedures described in this operator’s manual may create one or more
safety hazards, damage the ATO-250 or the device under test, or cause errors in the test results.
Vanguard Instruments Company, Incorporated assumes no liability for unsafe or improper use of
the ATO-250.

ATO-250™ Operating Procedures
Table of Contents
1.0 Introduction............................................................................................................................... 1
2.0 Supersedure Notice................................................................................................................... 1
3.0 General Description.................................................................................................................. 1
4.0 Furnished Test Accessories....................................................................................................... 2
5.0 ATO-250 Specifications ........................................................................................................... 2
6.0 Controls and Indicators............................................................................................................. 3
7.0 Preset Setup............................................................................................................................... 5
8.0 ATO-250 Printer Paper............................................................................................................. 6
9.0 ATO-250 Cable Connections.................................................................................................... 6
10.0 Operating Procedures.............................................................................................................. 8
11.0 Run Test Procedure................................................................................................................. 8
12.0 Enter Test Information Procedure......................................................................................... 11
13.0 Restore Record Procedure..................................................................................................... 12
14.0 Review Record Procedure..................................................................................................... 14
14.0 Computer Interface & Set Time............................................................................................ 14
16.0 Erase Record Procedure........................................................................................................ 15
17.0 Calibration Check procedure ................................................................................................ 16

ATO-250™ Operating Procedures
iv
LIST OF FIGURE
LIST OF TABLES
Figure 1.0 Controls and Indicators................................................................................................. 3
Figure 2.0 90 to 130Vac Jumper Setting ....................................................................................... 5
Figure 3.0 210 to 240Vac Jumper Setting ..................................................................................... 5
Figure 4.0 ATO-250 Cable Connection........................................................................................ 6
Figure 5.0 Step-by-Step Operating Procedures ............................................................................. 7
Figure 6.0 Typical ATO-250 Test Report.................................................................................... 11
Figure 7.0 Typical Test Record Directory Print Out ................................................................... 15
Figure 8.0 Bus Bar Connection.................................................................................................... 17
Table 1.0 ATO-250 Specifications and Leading Particulars ......................................................... 2
Table 2.0 Functional Description of Controls and Indicators........................................................ 4
Table 3.0 Input Power Voltage Selections..................................................................................... 5

ATO-250™ Operating Procedures
1
1.0 Introduction
1.10 Applicability
This manual applies to the Series II of the
model ATO-250™, identified by the part
number VIC-25000-S2 manufactured by
Vanguard Instruments Company. A
separate manual applies to the Series I, the
first design configuration of the Model
ATO-250.
2.0 Supersede Notice
This Operator’s manual is the basic issue for
the Series II model ATO-250and does not
supersede any previously published manual.
3.0 General Description
The ATO-250™ is a digital micro-ohm
meter designed for precisely measuring non-
inductive resistances ranging from 1 micro-
ohm to 300 milliohms. Applications include
resistance measurement of circuit-breaker
contacts, bushing joints or any other low
resistant devices. The test unit is field-
portable, rugged and can be easily operated
by first time users. The ATO-250 is built
with a 16-key pushbutton pad for entering
test parameters and control functions.
Control-option menus, measured resistance
values and other related identifying data are
outputted onto a LCD screen. The ATO-
250has a built-in thermal printer, which
prints test data onto a 2.5 inch wide
thermally sensitive paper.
Thus, the measured resistance data can
either be displayed or be printed from the
thermal printer. The measured resistance
data can also be stored in the FLASH
EEPROM, where up to 63 records of 96
readings each can be retained. Operators can
recall the stored resistance measurements
and related data at a later time for review
and printing.
A Windows based software package is
supplied with each ATO-250 that allows the
user to retrieve test records stored in the
unit’s memory. Operation requires little
more than connecting the test leads to an
unknown resistance, selecting the test
parameters, and test current (10 to 250
amperes).
3.1 Functional Description
The fundamental operation of the ATO-
250is based upon the electrical
relationship described by Ohm’s law:
R=V/I. Where Iis a known test current and
Vis the voltage across the unknown
resistance, such as breaker contacts. Since
the test current through the device under test
is known and the voltage across it is read by
the microprocessor, the resistance of the
device is calculated using Ohm’s law.
The ATO-250test voltage is supplied by
an unfiltered DC (direct current) power
supply. The DC test current ranging from 10
to 250 Amperes is set by a “CURRENT
CONTROL” knob on the front panel.
The ATO-250can make precise micro-
ohm measurements possible without
compensating for the error induced by the
test leads’ resistance, by running the
voltmeter test leads separately from the
current bearing test leads. Therefore, by
measuring the voltages at the terminals of
the resistance being measured eliminates the
error from the I•R voltage drop in the test
current cables.
Resistance readings are then displayed onto
a backlit 4-line by 20-character LCD.
NOTE
The ATO-250 test voltage is a full-
wave rectified DC, which is not a pure
DC voltage. At 25 Amperes or more of
test current, a circuit breaker bushing
CT may detect an AC (alternate
current) ripple through the breaker’s
contact. Precaution should be taken to
eliminate the CT sensing or any
accidental tripping of the Substation
Bus Differential Relay.

ATO-250™ Operating Procedures
2
4.0 Furnished Test Accessories
The ATO-250is supplied with a canvas
bag, a power cord, a roll of 2.5-inch-wide
printer paper and one set of 35-foot test
cable with heavy-duty alligator clamps.
Optional heavy-duty, welding-type C-
clamps are also available instead of alligator
clamps.
A heavy duty shipping case is available as
an accessory.
5.0 ATO-250 Specifications
(Refer to the specification list in Table 1.0)
ATO-250 specifications and leading
particulars are listed in Table 1.0.
Table 1.0 ATO-250 Specifications and Leading Particulars
MODEL ATO-250 (part number VIC-25000-S2)
TYPE Special-purpose test equipment, portable, 250 Amperes
digital micro-ohm meter
POWER 85 to 132 Vac or 200-240 Vac (selectable), 50/60 Hz
SIZE (inches) 16.8 wide by 12.6 high by 10.6 deep
WEIGHT Less than 42 lbs
TEST CURRENT 10 to 250 amperes
READING RANGE 1 micro-ohm to 300 milliohms
ACCURACY 1% reading, 1 count
DISPLAY LCD, 4-line by 20-character, backlit
CONTROLS Keypad: 10 number keys and 6 function keys
COMPUTER INTERFACE RS-232C
PRINTER Thermal printer (prints on 2.5 inch-wide thermal paper)
ENVIRONMENT Operating: 0C to 55C; Storage: -40C to 65C
FURNISHED One power cord, one set of 35-foot test cable,
One canvas bag
EXPENDABLES Paper, thermally sensitive, 2.5 inch wide roll
(VIC part # TP-3)
WARRANTY One-year warranty on parts and labor;
Post warranty service contracts available
NOTE:
▪THE ABOVE SPECIFICATIONS ARE VALID AT NOMINAL OPERATING VOLTAGE AND AT A TEMPERATURE OF 25  C
(77  F)
▪ATO-250 SPECIFICATIONS MAY BE UPGRADED AND CHANGED WITHOUT PRIOR NOTICE.

ATO-250™ Operating Procedures
3
6.0 Controls and Indicators
(See Figure 1.0 and refer to Table2.0)
The controls and indicators of the ATO-250
are shown in a control-panel illustration in
Figure 1.0. The pointing leader lines refer to
each item in the figure with an index
number. Each index number is cross-
referenced to a functional description in
Table 2.0. Although the purpose of these
controls and the display may seem obvious
and intuitive, users should become familiar
with them before attempting to use the
ATO-250. Misuse of the ATO-250 controls
can create serious hazards and cause loss of
data, and equipment damage. First-time
users should also review and become
familiar with the Safety Summary located in
the front section of this manual.
Figure 1.0 Controls and Indicators

ATO-250™ Operating Procedures
4
Table 2.0 Functional Description of Controls and Indicators
Fig. 1
Index #
Adjacent Panel Marking
Functional Description
1
None (typical at 2 places)
Red, voltage-sensing, input jacks.
2
None (typical at 2 places)
Red, test-current, output jacks.
3
HIGH CURRENT
PRESENT
Red, indicator LED. This is to warn operators
of the presence of high current, which can
“kick” high voltage if the current lead is
disconnected.
4
120/240 Vac, 8A, 50-60Hz
I/O
Input power connector with third wire safety
ground and 10A built-in circuit breaker.
5
RS-232C
9-pin, female, DB type, serial interface-port
connector.
PIN SIGNAL
2 Rx
3 Tx
5 Signal Gnd
6
CURRENT
CONTROL
Rotary knob used for adjusting test-current
level from 10 to 250 Amperes.
7
None
4-line by 20-character, backlit, LCD screen.
Use for displaying menu selections, prompts
and test-result data.
8
None
Keypad consisting of momentary-contact
pushbuttons. Ten alphanumeric keys and six
function keys.
9
None
Built-in thermal printer for outputting test result
data on 2.5 inch wide thermal paper.
6.1 ATO-250 LCD Contrast Control
To darken the LCD screen, press and hold
the “Paper Contrast” switch for two
seconds. To lighten the LCD screen, press
and hold the “Paper Contrast” switch for
two seconds.
6.2 ATO-250 Printer Control
To advance the printer paper, press “Paper 
Contrast” switch once. Paper will advance
from printer. Press “Paper Contrast”
switch once, paper will advance backward
from printer.
6.3 RS-232C Computer-Interface port
A Windows based software package is
supplied with each ATO-250, which allows
the user to retrieve test records stored in the
ATO-250 memory.

ATO-250™ Operating Procedures
5
7.0 Preset Setup
7.1 Operating Voltages
The ATO-250 operating voltages are
selectable between 90-130 Vac, 50/60Hz or
210-240 Vac, 50/60Hz. Voltage selection is
set by jumpers on a terminal block as shown
in Table 3.0 and in Figures 2.0 and 3.0.
Table 3.0 Input Power Voltage Selections
VOLTAGE SELECTION
TERMINAL BLOCK JUMPERS
90—130 Vac
Brown to Blue and Yellow to Green
210—240 Vac
Blue to Yellow
Figure 2.0 90 to 130Vac Jumper Setting
Figure 3.0 210 to 240Vac Jumper Setting
120Vac Jumper
Installation
220Vac Jumper
Installation

ATO-250™ Operating Procedures
6
8.0 ATO-250 Printer Paper
The ATO-250 printer uses 2.5 inch wide
thermal paper for printing test results.
Vanguard Instruments recommends that to
maintain the highest quality printing and to
avoid paper jamming, use paper supplied by
the factory. Paper can be ordered from the
following two sources:
Vanguard Instruments Co, Inc.
1710 Grevillea Court
Ontario, CA 91761
Tel: [phone]
Fax: [phone]
Part Number: TP-3 Paper
OR
BG Instrument Co.
13607 E. Trent Avenue
Spokane, WA 99216
Tel: [phone]
Fax: [phone]
Part Number: TP-3 paper
9.0 ATO-250 Cable Connections
The ATO-250 is supplied with a set of 35
foot test cable. Each cable consists of a
current-carrying cable and a voltage-sensing
cable. The current-carrying cable is
terminated with a 250 Amperes, male plug.
The sensing cable is terminated with a 25
Amperes, female plug. Insert the current-
cable plugs and voltage-sensing plugs into
their respective control-panel jacks as shown
in Figure 4.0. Ensure that the smaller,
voltage plugs are inserted into jacks
adjacent to their companion larger, current
jacks.
Figure 4.0 ATO-250 Cable Connection

ATO-250™ Operating Procedures
7
Figure 5.0 Step-by-Step Operating Procedures

ATO-250™ Operating Procedures
8
10.0 Operating Procedures
Before novice operators use the ATO-250 to
measure any resistance, they should review
Figure 5.0, the Step-by-Step Operating
Procedures for the ATO-250. The figure
shows the flowchart of the branching of the
multiple test options. The ATO-250
operation is simple, thus requiring minimal
input. The operator only needs to select
choices from the display menus and
responding to the displayed prompts.
10.1 Precautions
The purpose of the ATO-250 is to measure
non-inductive low resistance devices such as
high-power, circuit-breaker contacts.
WARNING
Do not measure resistance of any
inductive device, which will create an
unsafe, high-voltage spike due to the
collapsing of the magnetic field if the
test current is interrupted by a
detachment of a test lead. Do not
disconnect or touch any test lead
connected to a device being tested
while current is being conducted.
Failure to heed this warning can
result in personal injury and damage
to the ATO-250.
If the resistance of an inductive device
is desired, Vanguard Instruments does
manufacture the WRM, an instrument
designed for that purpose.
10.2 Preparations
a. Plug the ATO-250 power cable into a
120-volt power outlet. If the unit is setup for
240-volt operation, plug the power cable
into a 240-volt outlet receptacle.
b. Insert the test-current cable plugs and the
test voltage-sensing cable plugs into the
respective control-panel jacks.
c. Attach the opposite terminals of the test-
cable clamps to the resistive load that is to
be tested. (See Figure 4.0)
NOTE
It is important that the test clips be securely
attached to the contact bushings, bus bar or
junction terminals to eliminate errors from
contact resistance, due to the possibility that
the test currents can be as high as 250
Amperes.
d. To turn on the ATO-250’s power, press
“I” on the rocker switch. (Item 4 in Figure
1.0)
Observe that after the configuration data is
displayed briefly, then the START UP menu
is shown:
11.0 Run Test Procedure
A resistance may be measured by
performing the following step-by-step
sequence. However, if a test is to be fully
documented, the identification data must
also be entered for the equipment that is to
be tested. See Section 12.0 for entering the
identification data. Since the test time and
date will be stored with test record, the clock
and date must be also be correct before any
test is performed.
a. Press the number one key on the START-
UP menu. The CONNECT CABLES prompt
will display:
b. Slowly turn the CURRENT CONTROL
knob until the desired test current is shown.
CONNECT CABLES THEN
ADJUST DRIVE TO
DESIRED CURRENT
(250 A MAX)
1.RUN TEST 05/15/01
2.SETUP 10:28:23
3.CAL CHECK

ATO-250™ Operating Procedures
9
A ten second counter will start counting
down when the user starts selecting the test
current. The counter displays the remaining
seconds between the brackets on the second
line.
NOTE
If the user fails to select the test current and
also fails to press the START key within ten
seconds, the ATO-250 will terminate the
test.
c. When the desired current is set or
displayed, press the START key to begin the
burn-in cycle. The red HIGH CURRENT
PRESENT indicator will begin flashing.
The ATO-250 will burn-in the test load for
five seconds. A five second counter is also
shown on the display as illustrated below.
d. At the end of the burn-in period, the test
results are outputted:
e. After the resistance reading is fully noted,
press the ENTER key. The PRINT prompt
displays:
f. Press the number one key (YES) if the test
result is to be printed. A typical test report
printout is shown in Figure 6.
After the test result is printed, the KEEP
THIS READING? prompt will appear.
If a printout of the test record is not needed,
then press the number two key (NO), in
which case, the following prompt is
presented:
g. If the resistance reading needs to be saved
inside the working buffer, press the number
one key. If not, press the number two key
and go to step h.
The PREVIOUS DATA IN BUF message
will appear as shown below:
The user can append the new test data to the
previous test inside the working memory.
This feature is handy when a test was
interrupted and the ATO-250 was powered
off.
The previous test data time and date will be
displayed on the LCD screen.
h. Press the number one key (APPEND
PREV DATA) to store the present test result
in the working memory plus the test results
from the previous test before the ATO-250
was powered down.
PRESS “START” TO
BEGIN BURN-IN. [02]
50.0 AMPS
BURN-IN [05]
100.0 MILLI-OHMS
50.0 AMPS
FINAL RESISTANCE
I = 50.0 AMPS
101.0 MICRO-OHMS
PRINT TEST RESULTS?
1.YES
2.NO
KEEP THIS READING?
1.YES
2.NO
PREVIOUS DATA IN BUF
10/20/01 06:28:11
1.APPEND PREV DATA
2.CLEAR PREV DATA

ATO-250™ Operating Procedures
10
i. If the user only wants to keep the current
test result in the working memory, press the
number two key (CLEAR PREV. DATA)
which then prompt the TEST SAVED
acknowledgement. Press the ENTER key to
continue.
j. After the TEST SAVED advisory
displays, press the ENTER key to display
the RUN ANOTHER TEST? option.
k. To run another test, press the number one
key (YES). The display will start again at
step 11.a.
l. If no further testing is needed on the
present test set up, then press the number
two key (NO).
The prompt, PLEASE TURN CURRENT
CONT ROL TO ZERO, as shown below,
reminds the user to turn back the current
control knob to zero.
m. The user needs to set the CURRENT
CONTROL knob to zero to continue further.
n. If the user selected NO under RUN
ANOTHER TEST, then the SAVE THIS
RECORD display is shown next:
o. To save the record into the FLASH
EEPROM, select the number one key
(YES). The ATO-250 will assign a record
number automatically as shown below:
p. The user can press the ENTER key to
return to the START UP menu.
q. Press the number two key (NO) from the
SAVE THIS RECORD command and the
next prompt will be:
r. Press the number one key if the test data
is not to be saved and to return back to the
START UP menu.
s. If the user has a change of mind and
would like to save the test data, then press
the number two key. The following display
confirms that the test record has been saved:
t. Press the ENTER key and the display
returns back to the START-UP menu.
This completes the RUN TEST Procedure.
TEST SAVED
RUN ANOTHER TEST?
1.YES
2.NO
PLEASE TURN CURRENT
CONTROL TO ZERO
SAVE THIS RECORD
1. YES
2. NO
RECORD NUMBER 2
HAS BEEN SAVED !
ARE YOU SURE?
DATA WILL BE LOST!
1.DO NOT SAVE RECORD
2.SAVE RECORD
RECORD NUMBER 2
HAS BEEN SAVED !

ATO-250™ Operating Procedures
11
Figure 6.0 Typical ATO-250 Test Report
12.0 Enter Test Information Procedure
To fully document a test, the necessary
identification must be entered before
commencement of measurement. The test
identification will be stored with the
resistance reading record inside the memory.
a. Press the number two key (SETUP) from
START UP menu. The second SETUP
menu is shown below:
NOTICE
The following steps require the operator to
enter the identification data by pressing the
keys to enter each character of the prompted
input. The keypad, Item 8 in Figure 1, is
marked like a telephone keypad and is
utilized as described below. For example,
consider the alphanumeric key 2/ABC.
Press the key once to select the number “2.”
Press the key a second time to select the
letter “A.” If the key is pressed a third time,
letter “B” will be selected. While the fourth
time, will select the letter “C.” Pressing the
key a fifth time will return the display to the
number “2.” Additional pressing of the same
key will repeat the previously described
sequence.
Selections from the rest of the alphanumeric
keys are performed in the same way as
described above.
When a character entry is completed and
appears in the display at the cursor position,
the cursor is advanced to the next position
by pressing the key or backed-spaced by
pressing the key. To delete a character
press the CLEAR key. When all character
entries are completed, press the ENTER key
to set the identifying data into the storage
registers and to advance to the next
identification prompt.
2
ABC
1. ENTER ID
2. REVIEW RECORD
3. RESTORE RECORD
4. NEXT PAGE

ATO-250™ Operating Procedures
12
b. On the second SETUP menu, press the
number one key, ENTER ID. The next
display will appear:
c. Key in the necessary characters of the
name of the utility COMPANY. Then press
the ENTER key. The STATION ID prompt
appears next:
d. Select the respected characters of the
STATION name. Then press the ENTER
key. The CIRCUIT ID prompt appears:
e. Key select the needed characters of the
CIRCUIT name, then press ENTER key.
The MANUFACTURER ID prompt
appears:
f. Select the desired characters for the name
of the MANUFACTURER. Then press the
ENTER key. The MODEL ID prompt
appears next:
g. Input the next characters for the MODEL.
Then press the ENTER key. The SERIAL
ID prompt will then appear:
h. Select the characters for the SERIAL
NUMBER. Then press the ENTER key.
The KVA RATING prompt will display:
i. Press the characters of the KVA RATING.
Then press the ENTER key. The
OPERATOR ID prompt appears next:
j. Place the characters for the name of the
OPERATOR. Press the ENTER key when
finished. The display will return back to the
START-UP menu.
13.0 Restore Record Procedure
Restoring a record allows the user to bring a
test record stored in the FLASH EEPROM
to the working memory. Once the record is
in the working memory, the test record can
now be viewed on the LCD or printed on the
thermal printer.
From the START-UP menu, Press the
number two key (SETUP).
a. On the second SETUP menu, press the
number three key (RESTORE RECORD),
which will display the following menu:
COMPANY:
STATION:
CIRCUIT:
MANUFACTURER:
MODEL:
KVA RATING:
OPERATOR:
1.ENTER ID
2.REVIEW RECORD
3.RESTORE RECORD
4.NEXT PAGE
1.RESTORE RECORD
2.DIRECTORY
3.ERASE RECORDS
SERIAL NUMBER:

ATO-250™ Operating Procedures
13
b. To restore a record, press the number one
key.
c. Press the number two key to scroll
through test record.
d. Press the number one key if the record
number that is to be restored is known. The
record number entry prompt will appear:
e. Key in the record number and then press
the ENTER key to restore the desired
record. The RECORD RESTORED
message will display:
f. When the record is restored, press the
ENTER key to review the restored record or
to print the review record. The menu below
displays:
g. Press the number one key to scroll
through the list of records, as shown below.
Alternately, the PRINT TEST RECORD can
be selected by pressing the number two key,
which will printout the test record and return
to the START-UP menu.
h. When the list scrolls to the record of
interest shown on the above display, press
the ENTER to display the date and time of
the test, shown next):
i. After observing the correct date and time
for the selected test, press the ENTER to
display the complete test record, shown
below:
j. When the stored record is viewed, press
the ENTER key to return to the START-UP
menu.
If there are multiple test results, Press the 
key to display the next test. Press the key
to display the previous test.
This completes the main procedure to
restore a record.
NOTE
The above test record has one test result.
RESTORE RECORD
1.ENTER RECORD NUMBER
2.SCROLL TO SELECT
RESTORE RECORD
NUMBER:
RECORD RESTORED!
REVIEW RECORD
1.SCROLL TEST RECORD
2.PRINT TEST RECORD
RECORD ID INFO:
1 TESTS
MM-DD-YY HH:MM:SS
TEST NUMBER 1
TEST CURRENT: 100 A
105 MICRO-OHMS

ATO-250™ Operating Procedures
14
14.0 Review Record Procedure
The user can review a test record residing in
the working memory by using the following
procedures.
From the START-UP menu, press the
number two key (SETUP) to display the
second SETUP menu, shown below:
a. Press the number two key (REVIEW
RECORD) to display the following menu:
b. Press the number two key to print the test
result. A typical test result printout is shown
in Figure 6.
c. Press the number one key (SCROLL
TEST RECORD) to review all test records
inside the memory.
d. See step 12.g to view the test record.
14.0 Computer Interface & Set Time
The user is required to put the ATO-250
under computer interface mode to retrieve
test records to a personal computer.
Beginning at the START-UP menu, press
the number two key (SETUP) to display the
second menu shown below:
a. Press the number four key (NEXT PAGE)
to display the following options menu:
b. Press the number one key (COMPUTER
CONTROL) to allow the ATO-250 to be
controlled by an IBM-compatible personal
computer. The computer interface (ITF)
mode advisory will display:
d. To end the Computer Interface mode,
press the STOP key, at which time the
display will return to the START-UP menu.
e. To set the date and time, press the number
two key (SET TIME) from step a.
f. To set the date, consisting of the month,
day and year will only require six key
selections.
g. To set the time in the format of hour,
minute and seconds, simply press the six
necessary buttons on the keypad. When the
date and time are correctly set, press the
ENTER key to return back to the START-
UP menu. This completes setting the date
and time procedure.
15.0 Print Record Directory
Beginning at the START-UP menu, press
the number two key (SETUP) to display the
second setup menu shown below:
1.ENTER ID
2.REVIEW RECORD
3.RESTORE RECORD
4.NEXT PAGE
REVIEW RECORD
1.SCROLL TEST RECORD
2.PRINT TEST RESULT
RECORD ID INFO:
1.ENTER ID
2.REVIEW RECORD
3.RESTORE RECORD
4.NEXT PAGE
1.COMPUTER CONTROL
2.SET TIME
COMPUTER ITF MODE
ENTER
MM-DD-YY
HH:MM:SS
1.ENTER ID
2.REVIEW RECORD
3.RESTORE RECORD
4.NEXT PAGE

ATO-250™ Operating Procedures
15
a. On the SETUP menu, press the number
three key (RESTORE RECORD), which
will display the following menu:
b. Select the number two key
(DIRECTORY) to show the menu below:
c. Press the one key to print a list of all the
test records.
d. Press the number two key to print the last
ten records stored inside the memory.
Following the selected printout, the display
returns to the START-UP menu.
A typical test record directory print out is
shown in Figure 7.0.
Figure 7.0 Typical Test Record Directory Print Out
16.0 Erase Record Procedure
The following procedure allows the user to
erase one, multiple or all records stored in
the FLASH EPROM.
Beginning at the START-UP menu, press
the number two key (SETUP) to display the
second setup menu shown adjacent:
1.ENTER ID
2.REVIEW RECORD
3.RESTORE RECORD
4.NEXT PAGE
1.RESTORE RECORD
2.DIRECTORY
3.ERASE RECORDS
PRINT DIRECTORY
1. FULL DIRECTORY
2. SHORT DIRECTORY

ATO-250™ Operating Procedures
16
a. On the second SETUP menu, press the
number three key (RESTORE RECORD), to
display the menu:
b. When the ERASE RECORD menu is
selected, the above menu displays. Press the
number one key to erase a single record.
c. If all records are to be erased, press the
number two key. An advisory note, ALL
RECORDS ERASED! will display next and
the unit will return to the START-UP menu.
c. Key in the record number to be erased
then press the ENTER key to confirm. The
following advisory displays:
d. Press the ENTER key to return the
display to the START-UP menu.
This completes the restore record procedure.
17.0 Calibration Check procedure
Calibration check allows the user to verify
the electronics of the ATO-250 is working
properly.
All of the procedures start at the START-UP
menu, shown below:
a. Press the number three key to begin the
CAL CHECK procedure. The instructions
for the next step will display as follows:
b. When test cables are attached to a
shorting bar, press the ENTER key. The
following prompt appears:
c. When the test current is set to 100
Amperes and the ENTER is pressed, the
following prompt displays:
d. Press the START key to begin the CAL
CHECK. The following advisory note is
shown:
ERASE RECORD
1. ERASE SINGLE RECORD
2. ERASE ALL RECORDS
ERASE RECORD
NUMBER:XX
RECORD NUMBER X
ERASED!
1.RUN TEST 05/15/01
2.SETUP 10:28:03
3.CAL CHECK
CALIBRATION CHECK
CONNECT SHORTING BAR
“ENTER” TO CONTINUE
PLEASE RAMP CURRENT
TO 100 A
THEN PRESS “ENTER”
PRESS “START” TO
BEGIN CAL CHECK
100.0 AMPS
BEGIN CAL CHECK
100.0 AMPS