TSI Instruments ALNOR MicroManometer AXD 550 User manual

®
A TSI Company
®
OWNER’S MANUAL
AXD 550
MicroManometer®

1
TABLE OF CONTENTS
General Description 2
Safety 2
Getting Started 3
Installing Batteries 3
Preparing the Instrument 3
Attaching the Optional Pitot probe 3
Attaching a MicroPrinter 4
Start-Up Sequence 4
Zeroing the Instrument 4
Clearing the Memory 4
The Display 4
Modes 4
AXD 550 Keypad and Menus 5
The AXD 550 Keypad 5
Primary Key Functions 5
Secondary Key Functions 6
Menu Selections 6
Menu Items 6
Using the AXD 550 7
Basic Functions 7
To Change Units 7
To Hold a Reading (For Storage or Printing) 7
Measurement Modes 7
Pressure Selection 8
Velocity Selection 8
Volume Selection 8
Data Storage 8
Troubleshooting 9
Maintenance 10
Service Information 11

2
The AXD 550 MicroManometer is a meter that
measures differential pressure. It is also capable
of measuring and displaying air velocity and
volume flow.
Functions are selected through a 7-key pad or an
RS232 serial port. With the exception of the
ZERO key, each key has dual functions. In
addition, the user can choose from among many
menu-driven items for added measuring
flexibility. Options such as units of measurement
and time-constant settings can also be selected.
The AXD 550 displays measurement results on a
liquid-crystal display (LCD), with additional
display segments for memory locations and units
of measure.
It features two built-in pressure ports for
attachment to the pressure source you will
GENERAL DESCRIPTION
measure. Optional hoses and pitot probes are
available.
The instrument’s memory can hold 100 readings
of pressure, velocity, or volume. For
convenience, memory can be organized into
sections called “pages.” All data is saved by the
instrument’s own battery-powered system.
Readings can also be printed out during
operation by an optional printer, or can be saved
for subsequent downloading. The RS232-C serial
connection attaches the AXD 550 to a printer or
personal computer.
The AXD 550 uses three (3) AA size alkaline
batteries for low replacement cost. The
instrument’s automatic shut-off option can be
used to conserve battery power.
• When using the instrument to check air
flow in an elevated workplace, make certain
that you can safely raise and hold the
instrument while making measurements.
This is especially important when you are
working on a ladder.
• Avoid catching hoses or attachments in
moving machinery.
SAFETY
• Use the instrument only for measurements
using air.
• Avoid any corrosive or other dangerous or
explosive gas mixtures.
Please dispose of used batteries
in a responsible manner.
WARNING
!
NOTICE

3
GETTING STARTED
Installing Batteries
The AXD 550 uses three (3) AA size non-
rechargeable batteries. The unit was shipped with
batteries not installed. You will find the batteries
in the instrument package.
unit off after a twenty minute period of keyboard
inactivity. To disable this feature, follow the
instructions in the menu selections section of this
manual.
Attach hoses to the pressure ports at the top of the
instrument. Do not exceed maximum pressure.
If desired, attach the wrist strap to the bottom of
the instrument.
Attaching the Optional Pitot Probe
To attach the probe for measuring air velocity:
• Remove the Pitot probe and rubber tubing
from their carrying case.
• Remove the protective caps from the probe
and save them for re-storing the probe later.
• Attach one section of flexible tubing to the
probe’s static pressure port, and another to
the probe’s total pressure port.
• Identify the (+) and (-) pressure ports at the
top of the AXD 550.
• Attach the tubing from the total pressure
port of the Pitot probe to the (+) port of the
MicroManometer.
• Attach the tubing from the static pressure
port of the Pitot probe to the (-) port of the
MicroManometer.
• Check to ensure that all tubing connections
are tight (see Figure 2).
To install the batteries:
• Loosen the battery cover screw on the rear
of the instrument (Figure 1).
• Slide the cover up and lift it out.
• Install the batteries over the pull strap,
taking care to observe each battery’s
polarity.
• Replace the cover and tighten the screws.
Note: When the batteries become low, the LCD
will show [LO BATT] above the reading. From
that point, you will have about one hour of normal
use left. If []comes on continuously and
replaces the reading, the battery voltage is too
low for accurate measurements and the meter will
turn itself off.
Always keep a replacement set of new batteries
available.
Preparing the Instrument
The unit is shipped with its auto shut-off feature
enabled. This setting will automatically turn the
Figure 1—Back view of instrument
TOTAL PRESSURE HOLE
STATIC PRESSURE HOLES
STATIC PRESSURE PORT
(TO - INPUT ON MANOMETER)
TOTAL PRESSURE PORT
(TO + INPUT ON MANOMETER)
Figure 2—Pitot probe

4
Attaching a MicroPrinter
Connect the 8521 to the AXD 550 before turning
on the instrument. The connector on the AXD 550
is a telephone-style jack.
To attach the printer:
• Grasp the 8521 integral cable at the
connector.
• Align the keyway.
• Gently push the connector into the AXD 550
until it is locked.
Start-Up Sequence
Each time you turn the instrument on, some basic
functions are tested. The following will occur:
• All the LCD segments will turn on.
• The current software revision level will be
displayed.
• The message [ ] will appear.
• The last unit of measurement will be
displayed.
• The meter will begin to measure.
Zeroing the Instrument
Before you begin taking measurements, the AXD
550 must be zeroed by following these steps:
• Most hand-held meters using differential
pressure sensors require a warm-up time.
Turn on your Alnor AXD 550 a minimum
of 5 minutes before zeroing and taking your
first measurements.
• Make sure there is no air flowing past a Pitot
probe. Also verify that none of the tubing is
pressurized by accidental squeezing.
• Press the ZERO key until [ ] appears
on the display.
The instrument will automatically zero its
readings. Repeat this procedure if necessary,
because at high resolutions the AXD 550 will
read small pressure changes.
Clearing the Memory
If this is the first time you are using the AXD 550,
clear the memory before using the instrument.
Clearing the memory is done with the following steps:
• Push CLR for three seconds.
• Push ↑until [ ] appears.
• Push ↵to clear memory.
The meter starts in RUN mode. It will display
measurement values associated with the unit last
used. If the value is OVERRANGE the display
will show [ ]; similarily if the instrument is
measuring an UNDERRANGE value the display
will show [ ].
The AXD 550 uses a 4-digit, 7-segment LCD.
As a result, measurements exceeding 9,999 of
a given unit of measure will be displayed in a
scientific notation format of XXEY. The actual
reading will be rounded to the nearest thousand,
XX. The Y indicates the number of zeros after
XX. For example, 12,751 is displayed as [ ].
The AXD 550 is measuring and averaging the
actual value of the reading, not the rounded
THE DISPLAY
scientific notation value. No accuracy loss will
be encountered. When printing the data on the
8521 MicroPrinter or downloading the data to a
host PC, the actual reading will be seen.
Modes
The AXD 550 operates and takes measurements
in the RUN mode. You may be in the RUN mode
or one of the menu selection modes.

5
VOL The VOL key prepares the AXD 550
for air volume measurements. After
pressing this key, you must indicate
whether you’re measuring by area, or
whether you’re measuring a round or
rectangular duct. Choose one of these
options by pressing the ↑or ↓key,
followed by the ↵key to make a
selection. After you make your
selection, use the ↑or ↓key to enter
the dimensions, then the ↵key to enter
the units.
MENU MENU allows you to select one of
several options. Use the ↑or ↓keys to
move through the choices. To choose a
selection, push ↵, or return to RUN
mode by pushing ON/OFF. The
MENU selections are as follows:
[] Changes memory page
[] Prints all stored data
[] Correction Factor
[] Enables or disables auto
shut-off
[] Scans meter voltages
[] This is only used by the
factory
[ ] Enables or disables the
serial port
[] Time constant selection
(See also Menu Selections, next page)
HOLD Pressing this key freezes data in RUN
mode for input to memory or output to
a printer. The display flashes. Pushing
HOLD again stores and prints your
data. Pressing ON/OFF returns you to
RUN mode without storing or printing.
UNIT The UNIT key allows you to select a
unit of measurement. The ↑and ↓keys
move through the choices. Use the ↵
key to accept a choice, or press ON/
OFF to return to RUN mode without
making changes.
AXD 550 KEYPAD AND MENUS
↵
ON
OFF
VOL
CLR
MENU
↑
HOLD
AVE
UNIT MEM
↓
ZERO
AXD550
MICROMANOMETER
WARNING
!
CAUTION
ON
OFF
VOL
CLR
MENU
↑
HOLD
AVE
UNIT
↵
The AXD 550 Keypad
Each key (except ZERO) has two different
functions. The primary function is shown above
the diagonal line on the key’s surface. The
secondary function is shown below the diagonal
line. A more detailed description of each
function follows.
In the RUN mode,
if a key is held for
less than three
seconds, the
primary function is
activated. When a
key is held for
more than three
seconds, the
secondary function
is activated. The
exceptions to this
are the ↑and ↓
keys. Because they
are used to move
between menu options, these keys do not
function in RUN mode.
The cycle time of the AXD
550 software may cause
the meter to react slowly to a key push. The
reaction time of a key push will vary with
different functions (1–3 seconds). Do not push
a key twice because of a slow response time.
Doing so may result in accidental activation
of a secondary function or duplication of a
desired function.
Primary Key Functions:
ON/OFF This key is used to turn the instrument
on or off when in the RUN mode. If
the instrument is in any other mode,
pressing this key will exit that function
and go back to the RUN mode without
making any changes.

6
Menu items (to select any of the following
press ↵):
Measurements stored in the instrument’s
memory are organized into pages. This
key changes the page onto which you
are saving your measurements. If there
is no stored data on the current page,
the page number will not increase. A
total of 100 sets, or lines, of data can be
stored. You may have 100 pages of one
line each, one page of 100 lines each, or
any combination of pages and lines not
exceeding 100 readings.
This copies all stored data to a
connected printer or computer. You
can abort the printout at any time by
pressing and holding the ON/OFF key.
The Correction Factor is an all-purpose
multiplying factor which is applied
when measuring velocities or volumes.
cF is set to 1.000 unless it is changed in
the menu. An annunciator (t) tells the
user when “cF=1.” cF is usually used
when air density conditions deviate
from standard. See Appendix E.
Select values with the ↑or ↓key, then
press ↵to accept them or ON/OFF to
reject them.
This automatic shut-off option can be
enabled or disabled by pushing ↑or ↓
to select [ ] or [ ], then pushing
the ↵key to enter your selection.
When enabled, the automatic shut-off
will power-down the AXD 550 after
twenty minutes of keyboard inactivity.
This diagnostic tool allows a user to
view important analog voltages within
the instrument. Pushing ↑or ↓views
the eight different channels, which
include the following:
— O V dc.
— 4.965 to 5.025 V dc.
— battery voltage (3.5 V fresh
batteries)
MEM
↓
HOLD
AVE
UNIT
↵
ZERO
MENU
↑
MEM
↓
MEM The MEMORY key is used to review
stored data. When it is pressed, the
display will show the current page
number. The ↑and ↓keys will move
you to any page you wish to review.
To examine data, press the ↵key.
If memory is empty, the unit
automatically jumps back to RUN
mode. Otherwise, you can return there
by pressing the ON/OFF key.
(See also PAGES in Data Storage)
ZERO The AXD 550 will zero the instrument
any time this key is pushed. To get a
proper zero, make sure no pressure
difference is applied across the ports
and no kinks are in the hoses.
(See also Zeroing the Instrument)
Secondary Key Functions:
↑and ↓These keys allow you to move or scroll
through menu selections in forward (↑)
or reverse (↓) order.
AVE If held for 3 seconds, the AVE key lets
you view the average of the current
page of measurements which has been
stored. Pushing ON/OFF returns you to
RUN mode.
↵This key accepts all selected choices
such as values and menu items. After
each entry, [ ] appears on the
display as the AXD 550 stores new
information.
Menu Selections
Pressing the MENU key activates the main menu.
Use the ↑and ↓keys to scroll through the
available selections. Once you find your desired
selection, choose it by pressing ↵. Pressing ON/
OFF exits the menu, returning you to RUN mode.

7
Factory use only.
Selecting this item allows the user to
enable (on) or disable (off) the serial
port.
• Press the ↵key.
• Using the ↑or the ↓key, scroll to
or .
• Press the ↵key.
• Press the ON/OFF key to return to
the RUN mode.
Note: the serial port must be when
interfacing to a computer. Keep the port
when not in use to conserve batteries.
USING THE AXD 550
tc allows you to select from five
different speeds of display response.
• A setting of 1 is a quick response.
• A setting of 5 is a slow response.
• The meter is always shipped with
tc=2.
See the Time Constant Averaging
section in Appendix B for the exact
method the AXD 550 uses to display
a series of measurements.
Basic Functions
To Change Units:
• Push the UNIT key until [ ] appears.
• Use the ↑and ↓keys to view new
measurement units.
• The display annunciator ▲will move to the
selected unit (see Figure 3).
• Push ↵to select a new measurement unit.
km/h
m/s
mph
fps
fpm
cf
Pa
mmH
2
O
inH
2
O
l/s
m
3
/h
cfm
Figure 3—Display with annunciator and units of
measure.
For example: To change the units of measurement
from feet per minute (fpm) to meters per second
(m/s):
• Push the UNIT key until [ ] appears.
• Push ↑until the display annunciator ▲
moves to m/s, selecting meters per second.
• Push ↵to select the measurement unit.
To Hold a Reading (For storage or
printing):
• Push the HOLD key briefly until the
measured value flashes.
• Push HOLD again to STORE this reading
to memory, or push ON/OFF to reject it
and return to RUN mode.
Measurement Modes
You can set the AXD 550 for pressure,
velocity, or volume measurement by pressing
the UNIT key.

8
Pressure Selection:
The AXD 550 is a pressure measuring instrument.
Its factory default setting is to measure pressure in
inches of water (in. H2O) or pascals (Pa).
Velocity Selection:
Air velocity measurement can be accomplished
using a Pitot probe.
The following equations are used for pressure to
velocity conversions:
Pressure in inches H2O Velocity = 4005
÷∆P (inches H2O) in
feet/min
Pressure in Pascals Velocity = 1.29 ÷∆P
(Pa) in meters/second
The velocity calculations assume standard
conditions. Use the cF menu option to adjust the
velocity or volume readings. (See Appendix E
for air density correction factors and Appendix D
for pressure to velocity conversion charts.)
Volume Selection
(or reviewing the latest area):
Air volume measurement is achieved by
multiplying a velocity reading by an area.
• When you press the VOL key, the [ ]
menu appears on the display and provides a
way to choose whether you are measuring
by area (in square units) or by a round or
rectangular cross-section.
• Make your selection by scrolling using the
↑and ↓keys, then pressing the ↵key to
accept your choice.
• If you choose to use a cross-section, you
must then indicate dimensions as follows.
Area (review or select new value):
• When selected, [ ] flashes the current
units ft2[ ] or m2[ ].
• The display will then show the last area
value selected in ft2or m2.
• Modify these values by using the ↑and ↓
keys to change the volume, pressing the ↵
key to accept the value.
Rectangular:
• After [ ] is selected, the units of linear
distance will be flashed briefly in inches or
meters.
• The display will then show starting X
dimension values [ ] in inches or [ ]
meters. Accepting the X value affects choice
of a volume dimension (e.g. cfm).
• Change these values using ↑or ↓. Press the
↵key to accept.
• The next display shows desired Y dimension
values of [ ] in inches or [ ] meters.
• Change these values using ↑or ↓. Press the
↵key to accept.
• Press the ↑or ↓key until the desired value
is reached, then press ↵to accept.
Round:
• The display will show starting point diameter
values [ ] in inches or [ ] meters.
• Change the value to the necessary diameter
using ↑or ↓. Press the ↵key to accept.
Data Storage
All measurements stored in the instrument’s
memory are recorded on pages. A page is created
whenever:
• the unit of measurement changes,
• or page is selected from the MENU.
For example, if you are measuring feet per
second and decide to take measurements in miles
per hour, a new page will be created.
The AXD 550 memory has a total capacity of
100 sets of data. This means you can have one
page of 100 lines, or one hundred pages of one
line, or any combination of pages and lines
totaling 100 readings.

9
Each time the HOLD key is pressed for the
“second” time, the instrument will store
measurements and the correction factor. Readings
are stored in battery-backed memory so that
powering off or changing batteries does not erase
readings. These stored readings will remain in
memory until they are cleared or if the instrument
is damaged or malfunctions.
A copy of this data can be obtained if a printer or
computer is attached to the instrument.
If a printer is connected:
• Press the MENU key, then the ↑or ↓key
until [ ] appears.
• Press ↵to print the data.
• To escape from the print routine, press and
hold the ON/OFF key until [ ]
appears, then press the ON/OFF key to
return to the RUN mode.
To erase stored data:
• Press the CLR key until [ ] appears.
• Push the ↑or ↓key until [ ] appears.
• Press ↵to clear the memory.
Note: Keep in mind that you cannot erase
individual pages. Clearing data erases every
page in the instrument’s memory.
TROUBLESHOOTING
Symptom Probable Cause/Corrective Action
Display shows [ ] The measured value is beyond the instrument’s
range. Be sure there is no applied pressure, then
press ZERO.
Display shows [ ] Connection between the meter and the sensor is
faulty. Turn the meter off, then turn it back on
again.
Display does not change Your meter could be in a mode other than RUN.
Press the ON/OFF key until the unit turns off.
Then turn it on and try again.
Your input might simply be very stable. Test
your meter by pinching the hoses.
Meter turns off after completing start-up cycle The batteries are too low for your meter start.
Watch for the [ ] indication just before the
meter turns off, then replace the batteries.
Meter turns off by itself Check the auto shut-off feature. Your batteries
are probably too low; replace them. If after 20
minutes your meter turns off again, disable the
auto shut-off feature.
Meter does not turn off Be sure your meter is in RUN mode, since it
must be in RUN mode to turn off.
Continued on next page