Scott Fetzer Meriam Process Technologies M203 User manual

User’s Manual 9R122-IR Rev 1
May, 2010
1
M203 Altimeter / Indicated Air Speed Tester
USER’S MANUAL
Meriam Process Technologies’ M203 Altimeter / Air Speed Teste
r
is a microprocessor based pressure sensing device used to
measure pressure up to 900 mm Hg relative to absolute zero.
When used in Pressure Measure Mode, pressure can be
displayed in a variety of engineering units. Select the ALT / IAS
engineering unit and the M203 converts to Altitude Mode fo
r
checking altimeter instruments. Pressing the TARE button from
A
ltitude Mode changes the M203 to Air Speed Mode for checking
air speed instruments.
A
timed leak test function is available for Pressure, Altitude and
A
ir Speed Measure Modes. Other features include a Min/Ma
x
capture, selectable damp rates and field re-calibration.
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Table of Contents
User Interface.................................................................................1
1. Keypad Functions..................................................................1
ON/OFF & BACK WKEY ......................................................1
MIN/MAX & UP SKEY.........................................................1
TARE & DOWN TKEY ........................................................1
PRGM & ENTER XKEY.......................................................2
BACKLIGHT KEY..................................................................2
2. Zeroing the Manometer.........................................................3
3. Program Mode.......................................................................7
Units Select................................................................................8
ALT / IAS (Altitude / Indicated Air Speed) Mode.......................9
Damp Rate Select .................................................................. 11
User Info Select (Accuracy, SW version, Mfr date, SN)......... 12
Auto Shut-Off.......................................................................... 13
Lockout Select........................................................................ 14
Header Name ......................................................................... 15
Contrast Select....................................................................... 16
Data Logging .......................................................................... 17
Leak Test................................................................................ 19
Re-Calibration......................................................................... 21
RE-CALIBRATION – 1 Point EDIT and START..................... 22
RE-CALIBRATION – 5 Point EDIT......................................... 23
RE-CALIBRATION – 5 Point START..................................... 24
RE-CALIBRATION – Restore Factory Defaults ..................... 25
Specifications.............................................................................. 26
Certification/Safety/Warnings...................................................... 27
Changing the Batteries ............................................................... 27
Contact Information..................................................................... 29

User’s Manual 9R122-IR Rev 1
May, 2010
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User Interface:
1. Keypad Functions
ON/OFF & BACK WKEY
Turns the manometer on and enters the unit into the Measure
Mode. Pressing the key while in the Measure Mode turns the
unit off. It also serves as a backspace key when editing in the
Program Mode. The  key takes the user out of a
programmable register without changing the previous setting.
Pressing this key repeatedly will return the user to the Measure
Mode and then shut off the manometer.
MIN/MAX & UP SKEY
In the Measure Mode activates the Min/Max function of the
manometer. When activated the minimum value is displayed on
the upper left of the display and the maximum value on the
upper right. This key also deactivates and resets this function.
The ckey is used to scroll through the programmable registers
when the unit is in the Program Mode. Once a programmable
register is selected the ckey can be used to edit that register.
TARE & DOWN TKEY
In the Pressure Measure Mode, toggles on/off the Tare
function. The Tare function nulls the applied pressure and sets
the display value to “0”. With Tare activated, the letter “T”
appears in the lower left of the display.
In the ALT / IAS Measure Mode (selected from Program Mode
under Units Select menu), the Tare button toggles between
ALTITUDE function and AIR SPEED function.
The dkey is used to scroll through programmable registers
when the unit is in Program Mode. Once a programmable
register is selected the dkey can be used to edit that register.
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PRGM & ENTER XKEY
Puts the manometer into the Program Mode from the Measure
Mode. When in the Program Mode, pressing this key selects
the programmable register to be edited (with prompt for
password if Lockout is set). After the register has been edited,
pressing the PRGM key enters the new setting into the
manometer’s non-volatile memory. This key also acts as a
forward space fkey when editing user inputs such as the
header name.
BACKLIGHT KEY
The BACKLIGHT key, represented by the standard light bulb
symbol, toggles the display backlight between on and off.

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2. Zeroing the Manometer
The M203 Precision Smart Manometer is a stable and precise
instrument. However, on occasion the M203 should have a new
zero taken. This is done to remove zero drift that can occur
since the manometer was last zeroed. The M203 can be zeroed
only if the new applied zero is within ±1% FS of the original
factory calibration zero. This prevents accidental zeroing at
atmospheric pressure or other relatively high pressures. If
outside this limit a “ZERO RANGE ERROR” message appears
and the manometer will not zero.
The M203 provides three mechanisms for re-zeroing:
1.Referenced to Absolute Zero: This traditional and
preferred method takes a “snapshot” of the measured
pressure when a vacuum of less than 100 microns Absolute
is applied to the sensor.
2.Factory Zero: This method restores the calibration curve
to the original zero taken at the factory. Note that this
feature is intended for comparison purposes, and should not
be used for real pressure measurement, as any zero-drift
since shipment will not be accounted for.
3.User-Adjusted Zero: This method allows the user to enter
any pressure value when a known reference is applied (for
example, the local barometric pressure reading). The
manometer will compare its actual measured value with the
entered value, and calculate a new zero reference based on
the offset.
1.To zero the manometer using Referenced to Absolute
Zero, start with the unit turned OFF and use the following
keystroke sequence:
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Keystroke Display
1. Press ON/OFF button. The display briefly shows the
header name and full scale range
in the last engineering units
selected. The manometer then
goes into the Measure Mode
showing the pressure and
engineering unit.
2. Connect the M203 to a
vacuum source capable of
100 microns absolute or
less.
3. Pull a full vacuum. Display should read close to zero.
(See note on next page)
4. Press MIN/MAX and
TARE keys at the same
time. (See Figure 1
below.)
Top line of display reads
“ZEROING SOURCE:” Bottom line
of display reads “REF TO ABS
ZERO”
5. Press the PRGM key. Top line of display reads “ZERO IN
PROGRESS” while bottom line
counts down from 9. Zeroing is
complete when unit returns to
Measure Mode.
Figure 1 NOTE: The M203 can be zeroed
only if the new applied zero is
within ±1% FS of the original
factory calibration zero. If outside
this limit a “ZERO RANGE
ERROR” message appears and
the manometer will not zero.
Contact the factory for support in
this case.

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2.To zero the manometer using Factory Zero, start with the
unit turned ON and in Measure Mode. Then use the
following keystroke sequence:
Keystroke Display
1. Press MIN/MAX and
TARE keys at the same
time. (See Figure 1
above.)
Top line of display reads
“ZEROING SOURCE:” Bottom
line of display reads “REF TO
ABS ZERO”
2. Press Sor Tarrow
key until desired zero
function is shown on
the bottom line.
Bottom line of display reads
“FACTORY ZERO”
3. Press the PRGM key. Zeroing is complete when unit
returns to Measure Mode.
NOTE: this feature is intended for comparison purposes only
and should not be used for pressure measurement as any
zero-drift since shipment will not be accounted for.
3.To zero the manometer using User-Adjusted Zero, start
with the unit turned ON and in Measure Mode. The use the
following keystroke sequence:
Keystroke Display
1. Apply a known, accurate
pressure source. This may
be true atmospheric pressure
from a reference barometer.
2. Press MIN/MAX and TARE
keys at the same time. (See
Figure 1 above.)
Top line of display reads
“ZEROING SOURCE:”
Bottom line of display reads
“REF TO ABS ZERO”
3. Press Sor Tarrow key
until desired zero function is
shown on the bottom line.
Bottom line of display reads
“USER ADJ. ZERO”
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4. Press the PRGM key. Top line of display shows the
current non-zero compensated
pressure value. Bottom line of
display shows the same value,
along with the engineering unit.
5. Press any of Sor Tarrow
key or the PRGM key to
begin editing.
Top line of display continuously
updates. Bottom line of display
data is ready for editing; the first
character location is blinking.
Example: set current
pressure value to 29.5 In Hg
@ 0º C Abs.
6. Press the Sor Tarrow key
to set the first digit to 0. Current: xxx.xx 0xx.xx INHG
Using the Sarrow key the
character sequence is 0 - 9,
(-) negative, (.) decimal point.
The (-) sign is used if your
location is below sea level.
7. When the User Adj. Value is
correct press the PRGM key. Cursor flashes to the right of “0”.
If an error is made use the
back space Wkey to move
the cursor back to the
incorrect digit. Press the UP
Sor DOWN Tarrow keys to
correct the value.
8. Continue this process until
the display reads as shown
at right.
Current: xxx.xx
029.50 INHG
9. Press the PRGM key to enter
the final value. Zeroing is complete when unit returns to Measure Mode.

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Note that the User Adjusted Zero feature will not accept
entries in altitude units (FEET or METERS). When the
current engineering unit is FEET, the User Adjusted Zero
function will automatically prompt for an entry in Inches of
Mercury @ 0º C. When the current engineering unit is
METERS, the User Adjusted Zero function will automatically
prompt for an entry in Millimeters of Mercury @ 0º C.
3. Program Mode
The Program Mode is used to configure the manometer for
Measure Mode operation. After the PRGM key is pressed in
Measure Mode, the top line of the display reads “PROGRAM
MODE”. The bottom line reads “UNITS SELECT”. Press the d
or Sarrow keys to scroll through the Program Mode to the
desired register. The configurable registers found in the
Program Mode are Units Select, Damp Rate Select, User
Info Select, Contrast Select, Data Logging, Leak Test and
Exit. Press the PRGM key to select any of these configurable
registers. The manometer can be put into Program Mode at
any time during Measure Mode operation by pressing the
PRGM key. If Lockout is set, the correct code must be entered
when prompted (see the User Info / Lockout section of this
manual for more information on Lockout).
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Units Select
The standard engineering units available on the M203 are:
Inches of Mercury at 0° C (in Hg @ 0° C) (absolute)
Millimeters of Mercury at 0° C (mm Hg @ 0° C) (absolute)
PSI (absolute)
Mbars (absolute)
Bars (absolute)
kPa (absolute)
Torr (absolute)
ALT / IAS - selecting this unit gives access to English
(knots, MPH and Feet) or Metric (km/h and Meters)
units.
To change the engineering units the manometer should be “ON”
and in Measure Mode. Then follow these steps:
Keystroke Display
1. Press the PRGM key. Top line reads “PROGRAM
MODE” and bottom line
reads “UNITS SELECT”.
2. Press the PRGM key. Top line reads “UNITS
SELECT” and bottom line
shows current engineering
unit.
3. Press the Sor Tarrow
key until desired engineer-
ing unit is displayed.
Engineering units on
bottom line of display
change.
4. Press the PRGM key to
select the engineering unit. Top line reads “PROGRAM
MODE” and bottom line
reads “UNITS SELECT”.
5. Press the Tarrow key. Bottom line reads “EXIT”.
6. Press the PRGM key. Display returns to Measure
Mode in new engineering
unit.

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ALT / IAS (Altitude / Indicated Air Speed) Mode
The model M203 is capable of displaying altitude (feet or
meters based on “U.S. Standard Atmosphere 1962” tables) and
air speed (knots, MPH or km/h). The ALT / IAS Mode is
selected from Program Mode in the Units Select menu. Once
ALT / IAS Mode is selected, the M203’s default measurement is
altitude. Pressing the “Tare” key nulls the prevailing barometric
pressure and converts the display to air speed indication. To
revert back to altitude the “Tare” key is toggled again.
To set up the M203 for ALT / IAS Mode use the following steps:
Keystroke Display
1. Press the PRGM key. Top line reads
“PROGRAM MODE” and
bottom line reads “UNITS
SELECT”.
2. Press the PRGM key. Top line reads “UNITS
SELECT” and bottom line
shows current
engineering unit.
3. Press the Sor Tarrow
key until “ALT / IAS” is
displayed.
Top line reads “UNITS
SELECT”
Bottom line reads “ALT /
IAS”.
4. Press the PRGM key. Top line reads “UNITS
SELECT” and bottom line
reads “ENGLISH”.
5. a. If ENGLISH units are
desired, press the PRGM
key.
(For METRIC units, Go To
Step 6.)
Top line reads “UNITS
SELECT” and bottom line
reads “KNOTS”. Note:
the altitude unit “FEET”
is associated with Knots.
5. b. If KNOTS unit are
desired, Go To Step 7.
(For MPH units, Go To Step
5.c.)
5. c. If MPH units are
desired, press the Sor T
arrow key until “MPH” is
displayed.
Top line reads “UNITS
SELECT” and bottom line
reads “MPH”. Note: the
altitude unit “FEET” is
associated with MPH.
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5. d. Go To Step 7.
6. If METRIC units are
desired, press the Sor T
arrow key
Top line reads “UNITS
SELECT” and bottom line
reads “METRIC”. Units
are set to METERS and
km/h.
7. Press the PRGM key. Top line reads
“PROGRAM MODE” and
bottom line reads “UNITS
SELECT”.
8. Press the Wkey. Manometer returns to
Measure Mode displaying
Altitude.
Important Notes:
1. Altitude is the default measurement when ALT / IAS
Mode is active.
2. If ALT / IAS Mode was active upon manual or automatic
shut off, ALT / IAS Mode will be restored upon cycling
power and altitude will be displayed.
3. When the M203 is displaying air speed and power is
turned off (manually or automatically), Program Mode is
entered, or the Tare key is pressed, the unit will be
returned to altitude display once power is cycled or the
unit is returned to Measure Mode. This is a feature
designed to prevent errors in air speed measurement,
necessary because of the tare function employed on
barometric pressure to arrive at air speed
measurements. Barometric pressure fluctuates with
changes in weather conditions. Reverting to altitude
measurement upon powering down, entering Program
Mode or pressing the Tare button forces a new tare
value to be taken prior to each air speed measurement
session.

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Damp Rate Select
Adjustable exponential type damping is available to steady the
display when measuring pulsating pressures. The M203 has a
range of damping rates; 0.1, 0.2, 0.5, 1, 2, 5, 10, or 25 seconds.
Damping is done by averaging new data from the pressure
sensor against previously collected data. The microprocessor
collects data from the sensor every 0.1 seconds. The display
updates every 0.5 seconds, showing the current 0.1 second
pressure reading. When set at 25 seconds, the display updates
every 0.5 seconds with the average of the previous 25 seconds
readings. Therefore, it takes up to 25 seconds from the time
pressure is applied until the manometer displays the full scale
applied pressure. Min/Max display updates every 0.1 seconds.
To set the damp rate:
Keystroke Display
1. Enter Program Mode by
pressing the PRGM key. Top line reads “PROGRAM
MODE”. Bottom line reads
“UNITS SELECT”.
2. Press the Skey.
Bottom line reads “DAMP
RATE SELECT”.
3. Press the PRGM key. Top line reads “DAMP
RATE SELECT”. Bottom
line shows current value.
4. Press the Sor Tkeys
until the desire damp rate
is displayed on the bottom
line.
Bottom line shows damp
rate settings in seconds.
5. Press the PRGM key. Top line reads “PROGRAM
MODE”. Bottom line reads
“UNITS SELECT”.
6. Press the Tkey.
Bottom line reads “EXIT”.
7. Press the PRGM key. Returns to Measure Mode.
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User Info Select (Accuracy, SW version, Mfr date, SN)
The User Info Select registers are designed to provide the user
with information on the hardware and software in the
manometer. This register provides read only information on the
sensor’s accuracy, software version, date of manufacture and
serial number. It also allows the user to edit the Auto Shut-Off,
Lockout and Start-Up Header Name features.
To access the User Info Select registers, follow the steps below.
To configure a User Info Select register, follow the steps shown
on the following page.
Keystroke Display
1. From the Measure Mode
press the PRGM key. Top line reads “PROGRAM
MODE” and bottom line
reads “UNITS SELECT”.
2. Press the Sarrow key
twice Bottom line changes to
“USER INFO SELECT”.
3. Press the PRGM key. Bottom line shows accuracy
4. Press the Sarrow key. Software version no. shown.
5. Press the Sarrow key. Manufacture date shown.
6. Press the Sarrow key.
See instructions to set
AUTO SHUT-OFF later in
this manual.
Top line reads “AUTO SHUT
OFF” and bottom line reads
“ENTER TO SELECT”.
7. Press the Sarrow key. Bottom Line shows Serial No.
8. Press the Sarrow key.
See instructions for using
LOCKOUT later in this
manual.
Top line reads “LOCKOUT
CODE” and bottom line reads
“ENTER TO SELECT”.
9. Press the Sarrow key.
See instructions for editing
the Header later in this
manual.
Top line reads “HEADER
NAME” and bottom line reads
“MERIAM”. The cursor
flashes at bottom left.
10. Press the Warrow
key to go back to “USER
INFO SELECT” screen.
Top line reads “PROGRAM
MODE” and bottom line
reads “USER INFO SELECT”.

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Auto Shut-Off
Enabling the Auto Shut-Off feature allows the manometer to
turn itself off after a user selected period of keypad inactivity.
Selectable options include DISABLED, 10 Minutes (which is the
factory shipped default), 20 Minutes, 30 Minutes, 45 Minutes
and 60 Minutes. Disabling this feature limits the manometer to
being turned off by using the ON/OFF key only.
To configure auto shut-off follow these steps:
Keystroke Display
1. Follow steps 1-6 in the
User Info Select table. Top line reads “AUTO
SHUT-OFF” and bottom
line reads “ENTER TO
SELECT”.
2. Press the PRGM key,
then the up or down arrow
keys until the desired shut-
off time is shown.
Top line reads “AUTO
SHUT-OFF” and bottom
line toggles to
“DISABLED”, “10”, “20”,
“30”, “45” and “60”
minutes .
3. Press the PRGM key. Desired Auto Shut-Off time
is selected, top line reads
“AUTO SHUT-OFF” and
bottom line reads “ENTER
TO SELECT”.
4. Press the left arrow
key three times. Returns to Measure Mode.
Note: The “Auto Shut-Off” timer is suspended during Data
Logging and Leak Test sessions to prevent accidental loss of
information. Auto Shut-Off is re-instated after completion of
Data-Logging or Leak Test sessions.
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Lockout Select
Enabling the Lockout feature prevents unauthorized users from
making changes to the configuration of the manometer. To
enter the Program Mode, the user must first enter the
“password” (two-digit Lockout Code) within approximately 40
seconds when prompted. Failure to enter the correct two digit
code within approximately 40 seconds will return the unit to
Measure Mode. Any two-digit numeric code can be
programmed. The factory Lockout Code of 00 (which is the
default as shipped from the factory) disables the Lockout.
To set the Lockout Code follow these steps:
Keystroke Display
1. From the Measure Mode
press the PRGM key. If the
Lockout is set, enter the
correct “password” when
prompted.
Top line reads
“PROGRAM MODE” and
bottom line reads “UNITS
SELECT”.
2. Press the up arrow key
twice. Bottom line reads “USER
INFO SELECT”.
3. Press the right arrow
key then the up arrow key
four times.
Top line reads “LOCKOUT
CODE” and bottom line
reads “ENTER TO
SELECT”.
4. Press the right arrow
key, then press the up or
down arrow keys to
change the first digit. Press
the right arrow key to
proceed.
Bottom line shows the old
Lockout Code. The cursor
flashes at the first
position while the value is
changed, the cursor
moves to the right
position once the right
arrow key is pressed.
5. Press the right arrow
key when the desired code
is set. Lockout is activated.
Top line reads “LOCKOUT
CODE” and bottom line
reads “ENTER TO
SELECT”.
6. Press the left arrow
key twice. Returns to Measure Mode.

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Header Name
Follow the steps below to edit the Header Name.
Keystroke Display
1. From the Measure Mode
press the PRGM key. Top line reads “PROGRAM
MODE” and bottom line
reads “UNITS SELECT”.
2. Press the up arrow key
twice. Bottom line changes to
“USER INFO SELECT”.
3. Press the PRGM key. Bottom line shows serial
number.
4. Press the up arrow key
five times. Top line reads “HEADER
NAME” and bottom line
reads “MERIAM”. The
cursor flashes at bottom
left.
5. If header is correct press
backspace key. If editing is
desired proceed to step 7.
Top line reads “PROGRAM
MODE” and bottom line
reads “USER INFO
SELECT”.
6. Press the left arrow key. Returns to Measure Mode.
7. Press the up or down
arrow keys to set the
correct alpha-numeric
value.
Displays a number between
0 and 9, a letter from A to Z,
/ or a blank space.
8. Press the right arrow
key to accept entry. Cursor advances one
space to right.
9. Repeat steps 8 and 9
until the desired Header is
shown.
10. If an error is made
press the back arrow key
until the cursor is over the
incorrect value. Follow step
8 to correct. Press the right
arrow key to advance the
cursor without changing
values.
11. When the Header is
complete press the PRGM
key until header accepted.
Top line reads “PROGRAM
MODE” and bottom line
reads “UNITS SELECT”.
12. Press the left arrow
key. Returns to Measure Mode.
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Contrast Select
The Contrast Select register allows the user to adjust the
character contrast of the LCD display to provide the best
visibility for the ambient light conditions.
To adjust the contrast, follow these steps:
Keystroke Display
1. From the Measure Mode
press the PRGM key. Top line reads “PROGRAM
MODE” and bottom line
reads “UNITS SELECT”.
2. Press the Skey three
times. Bottom line reads
“CONTRAST SELECT”.
3. Press the PRGM key. Top line reads
“CONTRAST SELECT”.
Bottom line shows a
numerical value.
4. Press the Sor Tkeys
to increase or decrease the
contrast value. A low
number gives maximum
contrast and a high number
gives minimum contrast.
LCD lightens or darkens
depending on the value
set.
5. Press the PRGM key. Top line reads “PROGRAM
MODE” and bottom line
reads “UNITS SELECT”.
6. Press the Wkey. Returns to Measure Mode.
If an error is made during the contrast adjustment, pressing the e
key returns the display to the previous contrast setting.

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Data Logging
Data Logging can be used to record pressure measurements.
Two record modes are supported: automatic and manual. In
automatic mode, a pressure value is captured every 5 seconds
for 20 minutes, resulting in 240 stored values. In manual mode,
a pressure value is captured each time the PRGM key is
pressed up to 240 values. The data collected during a logging
session can be viewed upon completion.
Keystroke Display
1. From the Measure Mode
press the PRGM key. Top line reads “PROGRAM
MODE” and bottom line
reads “UNITS SELECT”.
2. Press the up arrow key
five times. Bottom line reads “DATA
LOGGING”.
3. Press the PRGM key. Top line reads “DATA
LOGGING” and bottom
line reads “RECORD”.
4. Press the PRGM key. Top line reads “RECORD
MODE” and bottom line
reads “AUTO” or
“MANUAL”.
5. Press the PRGM key at
AUTO to start automatic
logging or at MANUAL to
start manual logging mode.
Top line reads
“RECORDING X” and
bottom line reads “XX.XX
UNITS”. AUTO records
value every 5 seconds.
Manual records value each
time PRGM key is pressed.
6. To stop recording values
at any time, press the
ekey.
Top line reads “DATA
LOGGING” and bottom
line reads “RECORD”.
7. To access recorded
values, press the ckey. Top line reads “DATA
LOGGING” and bottom
line reads “VIEW”.
8. To view recorded
values, press the PRGM
key.
Top line reads “DATA
LOG:
1” and bottom line
displays the value.
Continue pressing the c
key to view all values.
9. Press the ekey 3
times. Returns to Measure Mode.
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The Auto Shut-Off” timer is disabled for Data Logging sessions.
Be sure to end the session to re-enable the Auto Shut-Off timer.

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Leak Test
The Leak Test feature allows the user to determine the leak rate
in the pneumatic system being monitored. Once configured,
Leak Test monitors the measured pressure, altitude or air
speed over time and displays the leak rate in units per minute at
the conclusion of the test. The maximum configurable leak test
period is 1440 min (1 day). Pressing any key during the leak
test aborts the test.
To enable Leak Test follow these steps:
Keystroke Display
1. From the Measure Mode
press the PRGM key. Top line reads
“PROGRAM MODE” and
bottom line reads “UNITS
SELECT”.
2. Press the down arrow
key twice. Bottom line reads “LEAK
TEST”
3. Press the PRGM key. Top line reads “LEAK
TEST” and bottom line
reads “CONFIGURE”.
4. Press the PRGM key. Top line reads “Leak Test
Period” & bottom “X.X
MIN”.
5. Use the up, down & right
keys to input test period Bottom line reads desired period; Ex. “ 20.0 MIN”.
6. Press the PRGM key. Top line reads “LEAK
TEST” and bottom line
reads “CONFIGURE”.
7. Press the up arrow key
once. Top line reads “LEAK
TEST” and bottom line
reads “PRGM TO START”.
8. Press the PRGM key. Top line displays
MIN/MAX pressure values
at left/right. Bottom line
reads the current
pressure value and units.
At end of test period, top
line displays the leak rate
in units per minute.
Bottom line shows the
current pressure reading.
9. Press the PRGM key. Return to Measure Mode
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The “Auto Shut-Off” timer is disabled for Leak Test sessions. Be
sure to end the session to re-enable the Auto Shut-Off timer.

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Re-Calibration
The Manometer can be re-calibrated in the field for zero, span,
and linearity. The proper primary standards must be available
prior to calibrating the Manometer. These standards should
meet the accuracy requirements for your company or industry.
Meriam Process Technologies follows the guidelines
established by ANSI / NCSL Z540-1-1994 which requires that
the primary standard be 4 times more accurate than the unit
under test.
The re-calibration is not intended to replace the Factory Lab
Calibration Procedure. It is intended to correct the curve fit if
the actual sensor characteristics change slightly over time.
For sensors up to 200 PSI, Meriam recommends a ±0.0015% of
reading deadweight tester. If calibrating using inches or
millimeters of mercury, be sure to match the reference
temperature of mercury in both the M203 and the deadweight
tester. The reference temperature for these units in the M203 is
0º C.
1-point (within upper 50% of Full Scale), 5-point (nominal values
of 0%, 25%, 50%, 75% & 100% of Full Scale), and restore
factory default re-calibration options are offered. For the 5-Point
re-calibration, points 2, 3 and 4 can be adjusted within ±1% of
reading around the nominal values. Point #5 can be adjusted
within ±1% of reading around nominal. Point #1 is fixed at zero.
For example: for a 900 mm Hg Abs sensor (nominal 17 PSIA),
Point # 2 (25%) can be edited form 216 to 234 mm Hg Abs.
Point #5 (100%) can be edited from 891 to 900 mm Hg Abs.
The unit can only be re-calibrated if the calibration points are
within 5 times the accuracy of the original factory calibration
(e.g. @ 0.05% accuracy, the point limit is ±0.25% of Full Scale).
If the re-calibration procedure generates a new value outside
this limit the procedure will fail. In this case the unit would need
to be returned to the factory for service.
Once a re-calibration has been performed (either 1-point or 5-
point) the unit will continue to allow future re-calibrations only
with that type of re-calibration. In order to enable the other re-
calibration type, the user must first restore the re-calibration
data to the factory defaults.
User’s Manual 9R122-IR Rev 1
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22
RE-CALIBRATION – 1 Point EDIT and START
To perform a 1-point re-calibration, apply a pressure between
50% and 100% of Full Scale and then follow these steps:
Keystroke Display
1. With unit OFF, press
and hold the MIN/MAX
key, turn the unit on by
pressing the ON/OFF key,
then release MIN/MAX.
Top line reads “RE-CAL”.
Bottom line reads “EDIT”.
2. Press the up arrow key
until “START” is displayed
on the bottom line.
Top line reads “RE-CAL”.
Bottom line reads
“START”.
3. Press the PRGM key. Top line reads “RE-CAL
START”.
Bottom line reads “1-
POINT”.
4. Press the PRGM key. Top line reads “CAL
POINT” and bottom line
displays the cal point
value.
5. Press the up/down
arrow keys to edit the
selected digit. Use the
left/right arrow keys to
change the cursor position.
Value entered must be 50-
100% of FS.
Bottom line displays the
cal point value. The cursor
flashes at the first position
while the value is
changed, then moves to
the right position when the
right arrow key is pressed.
6. Press the right arrow
key while on the right most
digit to proceed.
Top line reads “APPLY:”
Bottom line displays the
“CAL POINT” value.
7. Apply the input pressure
indicated using an
appropriate reference
standard; press PRGM
key.
Top line reads “RE-CAL”.
Bottom line reads
“START”, Manometer has
been recalibrated.
8. Press the left arrow
key. Returns to Measure Mode

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23
RE-CALIBRATION – 5 Point EDIT
To edit the calibration points for a 5 Point re-calibration follow
the steps below.
NOTE: If the factory default values are acceptable, skip this
section and proceed to the re-calibration 5-Point START
procedure.
Keystroke Display
1. With unit OFF, press and
hold the MIN/MAX key, turn
the unit on using the
ON/OFF key, then release
Top line reads “RE-CAL”.
Bottom line reads “EDIT”.
2. Press the PRGM key. Top line reads “CAL POINT 1”.
Bottom line displays the cal
point value.
3. Press the up/down arrow
keys to edit the selected
digit. Use the left/right
arrow keys to change the
cursor position. Note: For
0% go directly to step 4.
Bottom line displays the cal
point value. The cursor flashes
at the first position while the
value is changed, then moves
to the right position when the
right arrow key is pressed.
4. Press the right arrow key
while on the right most digit
to proceed.
Top line reads “CAL POINT 2”.
Bottom line displays the cal
point value.
5. Repeat steps 3 and 4 for
CAL POINTS 2, 3, 4 and 5. Top line reads “CAL POINT
2/3/4/5”. Bottom line displays
the cal point value.
6. After editing CAL POINT
5 press the right arrow key
while on the right most digit
to proceed.
Top line reads “RE-CAL”.
Bottom line reads “EDIT”.
7. To perform the 5-point
re-cal, press the up arrow
key until START is
displayed on the bottom
line.
OR
To exit without
performing the 5-point re-
cal press the left arrow
key
Top line reads “RE-CAL”.
Bottom line, “START”.
Continue with 5-Point Re-
calibration procedure at step 3
on next page.
OR
Returns to Measure Mode.
User’s Manual 9R122-IR Rev 1
May, 2010
24
RE-CALIBRATION – 5 Point START
To begin the 5-point re-calibration procedure, turn the unit OFF
and follow the steps below.
Keystroke Display
1. Press and hold the
MIN/MAX key and turn the unit
on by pressing the ON/OFF
key.
Top line reads “RE-CAL”.
Bottom line reads “EDIT”.
2. Press the up arrow key until
“START” is displayed on the
bottom line.
Top line reads “RE-CAL”.
Bottom line reads “START”.
3. Press the PRGM key. Top line reads “RE-CAL
Bottom line reads “1-
POINT”.
4. Press the up arrow key until
“5-POINT” is displayed on the
bottom line.
Top line reads “RE-CAL
START”.
Bottom line reads “5-
POINT”.
5. Press the PRGM key. Top line reads “POINT 1 –
ZERO:”
Bottom line displays live
applied pressure.
6. Vent P1 and P2 ports to
atmosphere and
simultaneously press the
MIN/MAX and HOLD keys,
then release.
Unit takes new zero. Top
line reads “ POINT 1 -
ZERO:”
Bottom line displays live
applied pressure. POINT 1
has been taken.
7. Press the right arrow key
while on the right most digit to
proceed.
Top line reads “POINT 2 -
APPLY:”.
Bottom line displays the cal
point value to apply.
8. Apply the indicated cali-
bration point pressure using
external pressure standards.
After pressure is stable, press
the right arrow key.
Top line reads “POINT 3 -
APPLY:”.
Bottom line displays the cal
point value to apply.
9. Repeat step 8 for CAL
POINTS 4 and 5. Top line reads “POINT 4/5 -
APPLY”
Bottom line displays the cal
point value.

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25
10. Use up or down arrow keys
to select NO or YES when
asked “Save?” the Re-
Calibration data.
Top line reads “SAVE?”.
Bottom line reads “NO” or
“YES”.
11. Press the PRGM key at
YES to save the Re-Calibration
data or at NO to exit without
saving.
Top line reads “RE-CAL”.
Bottom line reads “START”.
Re-cal is complete.
12. Press the left arrow key. Returns to Measure Mode.
RE-CALIBRATION – Restore Factory Defaults
To restore the re-calibration data to the factory defaults, follow
these steps:
Keystroke Display
1. With unit OFF, press
and hold the MIN/MAX
key, turn the unit on using
the ON/OFF key, then
release.
Top line reads “RE-CAL”.
Bottom line reads “EDIT”.
2. Press the up arrow key
twice. Top line reads “RE-CAL”.
Bottom line reads
“RESTORE DEFAULTS”.
3. Press the PRGM key. Top line reads “RESTORE
DEFAULTS”.
Bottom reads “YES” or
“NO”.
4. Use the up and down
arrow keys to select YES
or NO when asked to
restore defaults.
Top line reads “RESTORE
DEFAULTS”.
Bottom reads “YES” or
“NO”.
5. Press the PRGM key at
YES to restore the Factory
Default Calibration data or
at NO to exit without
restoring.
Top line reads “RE-CAL”.
Bottom line reads
“RESTORE DEFAULTS”.
Factory defaults have
been restored.
6. Press the left arrow
key. Returns to Measure Mode.
User’s Manual 9R122-IR Rev 1
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Specifications
Type, Range and Display Resolution:
17.403 psia (900.0 mmHg) – XX.YYY (XXX.Y)
Minimum / Maximum Display Values:
Altitude: -2000.0 to +36,000.0 Feet
-609.6 to +10,972.8 Meters
Indicated Air Speed:
0 - 496.4 Knots (approx.)
0 - 571.3 MPH (approx.)
0 - 919.4 km/h (approx.)
Note: the barometric pressure value at time the TARE
button is activated will determine the maximum indicated
air speed.
Altitude Accuracy:
±0.02 % F.S. (F.S. = 900 mm Hg)
Indicated Air Speed Accuracy:
±0.028 % F.S. (F.S. = 900 mm Hg)
Accuracy statements include the combined effects of temperature,
non-linearity, repeatability, hysteresis and resolution.
Warm up time = 5 minutes.
Temperature:
Storage = -40°C to +60°C (-40°F to +140°F)
Operating = -5°C to +50°C (23°F to +122°F)
Media Compatibility:
AI: Absolute pressure sensors for use with gases and liquids
compatible with 316L SS
Pressure Limits:
AI units: 77 PSIA (4000 mm Hg Abs)
Connection:
1/8” female NPT, 316L SS. P1 is the pressure connection. P2 is not
accessible (factory plugged with metal disc)
User must use a wrench on the pressure manifold when installing
user’s 1/8” NPT fitting. Do not tighten the fitting without using a
wrench on the pressure manifold. Failure to use a wrench on the
manifold will damage the plastic enclosure and void warranty No
torque should be applied to the manifold with respect to plastic
enclosure.

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Battery Type:
4 each AA alkaline
Battery Operation:
>100 hours continuous use, 1 year shelf life, auto power off
programmable at Disabled, 10, 20, 30, 60 or 90 minutes
Enclosure: (6.9” × 3.8” × 2.3”) Polycarbonate, Permanently Static
Dissipative, ESD Protection
Enclosure with Boot: (7.2” × 4.2” × 2.5”)
Rating: IP 40
Certification/Safety/Warnings
Note the following cautions and requirements:
• Substitution of components may impair operation and safety
• Disconnect power before servicing.
• To prevent unsafe conditions,
 DO NOT mix old batteries with new or mix batteries
from different manufacturers
 DO NOT replace batteries in potentially hazardous
atmospheres
 DO NOT operate in potentially hazardous
atmospheres
• User must use a wrench on the pressure manifold when
installing user’s 1/8” NPT fitting. Do not tighten the fitting
without using a wrench on the pressure manifold. Failure to
use a wrench on the manifold will damage the plastic
enclosure and void warranty No torque should be applied
to the manifold with respect to plastic enclosure.
Changing the Batteries
The manometer is powered by four, 1.5 volt AA size batteries.
When the output of the batteries under load drops, the display
will alternate between “LOW POWER DETECT” and
“REPLACE BATTERY”. Low power may affect performance.
The unit should not be used to measure pressure in this
condition. All four batteries should be replaced.
To replace the battery locate the battery compartment at the
bottom rear of the manometer, as shown here.
User’s Manual 9R122-IR Rev 1
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28
Remove the two screws on either side of the battery cover by
turning them counterclockwise until the fully disengaged from
the manometer base. Lift the cover from the back of the unit.
Remove the batteries by pulling the positive side first straight
out of the battery compartment. Note the positive (+) and
negative (-) battery polarity markings at the bottom of the
compartment, as shown here.
To install the four batteries: 1) Make sure polarity of battery
matches the markings in the compartment. 2) 1st place the (+)
end of the battery into the bottom of the battery slot. 3) Then
push in (-) end of the battery until it is seated in the bottom of
the battery slot. The battery compartment has stand offs molded
into the side of the compartment. When a battery is installed
with the polarity reversed, the stand offs prevent the negative
battery terminal from contacting the positive terminal in the
battery compartment. The unit will not power up when a battery
is installed this way. Should this happen, simply reverse the
battery to align the polarity.
With the batteries secured in the battery compartment, replace
the compartment cover. The cover has only one correct
alignment. The “WARNING DO NOT OPEN IN EXPLOSIVE
ATMOSPHERE” statement on the battery cover must be visible
and aligned in the middle of the manometer case. To secure
the cover, torque the screws clockwise to 1.6-1.8 in-lbs. Do not
over tighten.

User’s Manual 9R122-IR Rev 1
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Contact Information
If the M203 can not be zeroed, recalibrated or is damaged, it
must be returned to the factory for servicing. In this case,
contact the Meriam Process Technologies representative in
your area or call the factory at the numbers listed below for a
Return Material Authorization (RMA) number.
Meriam Process Technologies
10920 Madison Ave.
Cleveland, OH 44102
Ph. [phone] FAX [phone]
E-mail [email protected]
Web www.meriam.com
Or contact our sales representative:
TetraTec Instruments GmbH
Gewerbestr. 8
71144 Steinenbronn
Deutschland
Tel: +497157 / 5387-0, Fax: +497157 / 5387-10
Internet: www.tetratec.de
Email: [e-mail]
All M203 Altimeter / Air Speed Testers recalibrated at the
factory are returned with certificates of NIST traceability.
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