Hach Ultra MET ONE 237AB User manual

701076
MET ONE 237AB Particle Detector
USER MANUAL
June 2008, Edition 5

701076
MET ONE 237AB Particle Detector
USER MANUAL
June 2008, Edition 5
© Hach Ultra Analytics, Inc., 2008. All rights reserved. Printed in the U.S.A.

1
Table of Contents
Section 1 Specifications.................................................................................................................... 3
Section 2 General Information......................................................................................................... 5
2.1 Safety information........................................................................................................................ 5
2.1.1 Use of hazard information................................................................................................... 5
2.1.2 Precautionary labels ........................................................................................................... 5
2.1.3 Laser safety information...................................................................................................... 6
2.1.4 Electrostatic discharge (ESD) considerations..................................................................... 6
2.1.5 Battery safety information ................................................................................................... 6
2.2 General product information ........................................................................................................ 7
2.3 Theory of operation...................................................................................................................... 8
Section 3 Installation.......................................................................................................................... 9
3.1 Unpack the instrument................................................................................................................. 9
3.2 Mechanical installation............................................................................................................... 10
3.2.1 Install the isokinetic probe................................................................................................. 10
3.2.2 Install the purge filter......................................................................................................... 11
3.2.3 Load printer paper............................................................................................................. 11
3.2.4 Connect the AC adapter ................................................................................................... 12
3.2.5 Install the RH/T probe ....................................................................................................... 12
3.3 Rear panel connections ............................................................................................................. 12
Section 4 System Start Up .............................................................................................................. 13
4.1 Power up.................................................................................................................................... 13
Section 5 Operation.......................................................................................................................... 15
5.1 Front panel overview.................................................................................................................. 15
5.2 Setup.......................................................................................................................................... 16
5.3 Counting modes......................................................................................................................... 16
5.3.1 Manual mode .................................................................................................................... 16
5.3.2 Automatic mode ................................................................................................................ 19
5.3.3 Concentration mode.......................................................................................................... 21
5.3.4 Beep mode........................................................................................................................ 23
5.4 Program the relative humidity and temperature probe (RH/T)................................................... 23
5.4.1 Environmental alarms .......................................................................................................24
Section 6 Maintenance .................................................................................................................... 25
6.1 Maintenance guidelines ............................................................................................................. 25
6.2 Clean the sensor........................................................................................................................ 25
6.2.1 Battery replacement.......................................................................................................... 26
6.3 Printer maintenance................................................................................................................... 26
6.3.1 Clean the print head.......................................................................................................... 26
6.3.2 Correct light print............................................................................................................... 26
6.3.3 Replace the printer ribbon.................................................................................................27
Section 7 Troubleshooting Procedures....................................................................................... 29
7.1 Common problems..................................................................................................................... 29
7.2 Reset the counter....................................................................................................................... 29
7.3 Pump troubleshooting................................................................................................................ 30
7.3.1 Disassembly and cleaning of the pump ............................................................................ 30
7.3.2 Pump optimization ............................................................................................................ 32
Section 8 Replacement Parts and Accessories......................................................................... 33
8.1 Accessories................................................................................................................................ 33
Section 9 Service Contact Information ........................................................................................ 35
Section 10 Limited Warranty .......................................................................................................... 37

2
Table of Contents
Section 11 Certification....................................................................................................................39
Appendix A Optional Accessories ................................................................................................41
A.1 Relative humidity/Temperature (RH/T) probe............................................................................41
A.2 High-pressure diffuser................................................................................................................41
A.3 RS485 converter ........................................................................................................................41
A.4 External printer...........................................................................................................................42
A.5 PortAll software..........................................................................................................................42
A.6 Carrying case.............................................................................................................................42
Appendix B Computer Interface Operations ..............................................................................43
B.1 Data analysis for ISO 14644......................................................................................................43
B.1.1 Computer communications ...............................................................................................43
Appendix C PortAll Software..........................................................................................................47
C.1 Connections...............................................................................................................................47
C.2 Operation ...................................................................................................................................47
Appendix D DPU–414 Printer..........................................................................................................49
D.1 Printer setup ..............................................................................................................................49
D.2 Counter setup for the printer......................................................................................................50

3
Section 1 Specifications
Specifications are subject to change without notice.
General
Size 170.94 mm x 58.42 mm x 165.10 mm (6.7" W x 4.5" H x 11.7" D)
Weight 3.0 kg (6.8 lb)
Maximum count displayed 9,999,999
Sample flow rate 0.1 cfm
Number of size ranges 2, 4, 5, 6 (specified at the time of order)
Particle size ranges
MET ONE 237A—0.5 and 5.0 micron (2 channel); 0.5, 0.7, 1.0 and 5.0 micron (4
channel); 0.5, 0.7, 1.0, 2.0 and 5.0 micron (5 channel); 0.5, 0.7, 1.0, 2.0, 3.0 and
5.0 micron (6 channel)
MET ONE 237B—0.3 and 5.0 micron (2 channel); 0.3, 0.5, 1.0 and 5.0 micron (4
channel); 0.3, 0.5, 0.7, 1.0 and 5.0 micron (5 channel); 0.3, 0.5, 0.7, 1.0, 2.0 and
5.0 micron (6 channel)
Coincidence error Less than 5% at 2,000,000 particles/cubic feet
Power +5 W, +10 V (approximately) (+6 V with battery pack)
Light source Laser diode
Sample/hold times 1 second to 24 hours
Count alarms 1 to 9,999,999 counts
Data storage 500 samples, rotating buffer
Count cycles Up to 100 in Auto mode
Locations Up to 250 (number appears on the printout)
Output RS232/RS485 for computer
Pump type Carbon-vane, 0.1 cfm
Battery type Rechargeable NiCd, 3500 mAH
Operation time 4 hours printing, 8 hours without printing
Environment
Operating temperature 2 to 29 °C (55 to 84 °F)
Operating humidity 10 to 85% relative, non-condensing
Storage temperature -40 to 71 °C (–40 to 160 °F)
Storage humidity Up to 98% relative, non-condensing

4
Specifications

5
Section 2 General Information
2.1 Safety information
Read this entire manual before unpacking, setting up or operating this equipment. Pay
attention to all danger and caution statements. Failure to do so could result in serious
injury to the operator or damage to the equipment.
To make sure that the protection provided by this equipment is not impaired, do not use
or install this equipment in any manner other than that specified in this manual.
2.1.1 Use of hazard information
DANGER
Indicates a potentially or imminently hazardous situation which, if not avoided, will
result in death or serious injury.
WARNING
Indicates a potentially or imminently hazardous situation which, if not avoided,
could result in death or serious injury.
CAUTION
Indicates a potentially hazardous situation that can result in minor or
moderate injury.
Important Note: Indicates a situation which, if not avoided, can cause damage to the
instrument. Information that requires special emphasis.
Note: Information that supplements points in the main text.
2.1.2 Precautionary labels
Read all labels and tags attached to the instrument. Personal injury or damage to the
instrument could occur if not observed. A symbol, if noted on the instrument, will be
included with a danger or caution statement in the manual.
This symbol, if noted on the instrument, references the instruction manual for operation and/or safety information.
Electrical equipment marked with this symbol cannot be disposed of in European public disposal systems after
12 August of 2005. In conformity with European local and national regulations (EU Directive 2002/96/EC),
European electrical equipment users must now return old or end-of life equipment to the Producer for disposal at no
charge to the user.
Note: To return for recycling, contact the equipment producer or supplier for instructions on how to return end-of-life
equipment, producer-supplied electrical accessories, and all auxiliary items for proper disposal.
This symbol, when noted on a product enclosure or barrier, indicates that a risk of electrical shock and/or
electrocution exists.
This symbol, if noted on the product, indicates the need for protective eye wear.
This symbol, when noted on the product, identifies the location of a fuse or current limiting device.
This symbol indicates a laser device is used in the equipment.
This symbol, when noted on the product, indicated the presence of devices sensitive to Electro-static Discharge
(ESD) and indicated that care must be taken to prevent damage with the equipment.

6
General Information
2.1.3 Laser safety information
This particle counter contains a laser-based sensor that is a Class 1 product (as defined
by 21 CFR, Subchapter J, of the Health and Safety Act of 1968) when used under normal
operation and maintenance. The manual contains no procedures for service of internal
parts within this unit. Service should be performed only by factory-authorized personnel.
The particle counter has been evaluated and tested in accordance with EN
61010-1:1993, "Safety Requirements For Electrical Equipment For Measurement,
Control, and Laboratory Use" and IEC 825—1:1993, "Safety of Laser Products".
2.1.4 Electrostatic discharge (ESD) considerations
Important Note: To minimize hazards and ESD risks, maintenance procedures not
requiring power to the analyzer should be performed with power removed.
Delicate internal electronic components can be damaged by static electricity, resulting in
degraded instrument performance or eventual failure.
The manufacturer recommends taking the following steps to prevent ESD damage to
the instrument:
•Before touching any instrument electronic components (such as printed circuit cards
and the components on them) discharge static electricity. This can be accomplished
by touching an earth-grounded metal surface such as the chassis of an instrument
or a metal conduit or pipe.
•To reduce static build-up, avoid excessive movement. Transport static-sensitive
components in anti-static containers or packaging.
•To discharge static electricity and keep it discharged, wear a wrist strap connected
by a wire to earth ground.
Handle all static-sensitive components in a static-safe area. If possible, use anti-static
floor pads and work bench pads.
2.1.5 Battery safety information
WARNING
An explosion can occur if the internal battery is replaced incorrectly.
Figure 1 shows the label that appears on the battery for the safety of the user.
Figure 1 Battery safety label

7
General Information
2.2 General product information
The MET ONE 237 particle counter is a battery operated, laser based particle counter
that is used in a walk-around sampling routine. The counter can store up to 500 records
for each sample with a different location label on the record. The data records may later
be printed or downloaded to a computer for analysis. The MET ONE 237 particle counter
is used in environments where the particulate contamination does not exceed two million
particles per cubic foot of air, such as clean-rooms, medical instrument assembly,
computer rooms. The Concentration mode in the MET ONE 227 particle counter is used
to take a brief sample and estimate the probable cleanliness for areas with unknown
particulate levels. This is based on built-in calculations performed in the microprocessor
of the counter. Long term use in uncontrolled environments such as open air office
spaces or outdoor air will require frequent user maintenance.
The MET ONE 237 particle counter operates at a flow rate of 0.1 cubic feet per minute
(cfm). The flow rate is required to set the sampling parameters. It takes 10 minutes to
sample one cubic foot of air while the results of a one minute sample is multiplied by ten
to obtain counts per cubic foot. All counts are reported as cumulative counts; that is, all
the reported 0.3 µm particles are 0.3 µm and larger in size.

8
General Information
2.3 Theory of operation
The MET ONE 237A/B particle counter is a compact, fully featured particle counter that
includes sensor, pump, electronics and the printer. Both the variants use the same
sensor, pump, CPU and display electronics. The MET ONE 237A particle counter is
calibrated with channel one sensitivity of 0.5 µm and the MET ONE 237B particle counter
is calibrated with a channel one sensitivity of 0.3 µm. Both operate at a flow rate of 0.1
cfm.
The sample passes through a laser beam in the sensor. The particles in the sample
scatter the laser light. The sample then passes through the pump and a filter to trap
particles in the counter. The flashes of scattered light are converted to electronic pulses
directly proportional to the amount of scatter to make a correlation to particle size. The
electronic pulses are counted and stored in channel bins in a data record which includes
the date and time from the CPU clock. If the RH/T probe is attached, snapshots of
environmental conditions are also included (refer to Figure 2 below).
Figure 2 Theory of operation
1Sample inlet 6Sample outlet
2Sensor 7Serial data out
3Flow monitor 8Printer
4Pump 9Control electronics
5Filter 10 Display

9
Section 3 Installation
DANGER
Only qualified personnel should conduct the tasks described in this section of
the manual.
This section describes the setup of the MET ONE 237 particle counter and connections to
the equipment. If necessary, contact the Technical Support Department with questions
regarding the compatibility or suitability of this product for a specific application.
3.1 Unpack the instrument
Remove the components from the shipping container and inspect for damage. Verify that
all items listed in Figure 3 are included. If any items are missing or damaged, contact the
manufacturer or sales representative.
Retain the original packaging materials. Use the original packaging material to store or
ship the instrument to protect against damage during storage or transportation.
Figure 3 List of packaged items
1Isokinetic probes—Wand style (Catalog No. 203015–3) 4MET ONE 237 particle counter
2Isokinetic probes—Direct mount (Catalog No. 2080613) 5Thermal printer paper (Catalog No. 460519)
3Purge filter (Catalog No. 2080442) 6AC adapter—115 VAC (Catalog No. 770007), 230VAC
(Catalog No. 770012), 100 VAC (Catalog No. 770009)

10
Installation
3.2 Mechanical installation
The MET ONE 237 particle counter is ready to use when unpacked. Check for all the
connections to the equipement.
3.2.1 Install the isokinetic probe
The isokinetic sample probes are used for accurate air sampling in particle counting
applications. The isokinetic probe (refer to Figure 3 on page 9, item1 or item 2) is used in
the laminar air flow for a flow rate of up to 100 feet per minute.
Isokinetic sample probes can be:
•Mounted directly on machines
•Suspended from the ceiling
•Mounted on the wall or through the wall.
Note: Make sure the the isokinetic probes are attached before sampling.
To install the isokinetic probe:
1. Remove the red sensor inlet cap from the MET ONE 237 particle counter.
Note: The isokinetic probes are protected with plastic caps on the openings and should remain in
place till they are used in order to minimize contamination.
2. Connect the isokinetic probe to the sensor inlet so that the open end faces the
direction of the air stream (refer to Figure 4).
Figure 4 Isokinetic probe connected to MET ONE 237 particle counter
1Isokinetic probe 2Sensor inlet

11
Installation
3.2.2 Install the purge filter
The purge filter (refer to Figure 3 on page 9, item 3) is used for maintenance (purge and
zero count) of the MET ONE 237 particle counter. The purge filter permits direct sampling
of pressurized air at pressures ranging from 30 to 150 psi.
Note: It is recommended that the purge filter be applied to the counter before moving the MET ONE
237 particle counter to avoid cross contamination.
Note: Verify the zero counts before moving the MET ONE 237 particle counter.
To install the purge filter:
1. Remove the red sensor inlet cap or the isokinetic probe from the MET ONE 237
particle counter.
2. Connect the purge filter to the sensor inlet.
3.2.3 Load printer paper
To load the printer paper:
1. Open the paper tray cover.
2. Remove any remaining paper from the last roll. Snip the paper at the spool and press
PAPER FEED until the paper tray is empty.
3. Trim the end of the new paper roll:
•To an arrow-shaped edge for a Seiko Printer (Figure 5)
•To a straight edge for a Fujitsu Printer (Figure 5).
Note: The Fujitsu printer has a paper tension release lever that must always be in the Down
position for proper operation. See Figure 5
4. Place the paper roll in the paper tray. Make sure that the paper roll is placed so that
the paper feeds through the feed mechanism from the bottom of the paper roll. See
Figure 5
5. Insert the tip of the paper roll into the slot in the feed mechanism (above the botom of
the paper tray).
6. Press PAPER FEED. The paper will be pulled through the printer.
7. Close the paper tray cover.
Seiko printer Fujitsu printer Paper tension release lever
Figure 5 Loading printer paper

12
Installation
3.2.4 Connect the AC adapter
The AC adapter (refer to Figure 3 on page 9, item 6) is used to charge the internal battery
and use the MET ONE 237 particle counter with a standard 115 VAC outlet.
To connect the AC adapter:
1. Turn off power to the MET ONE 237 particle counter.
2. Attach the AC adapter to the power input jack (refer to Figure 6 on page 12) at the
back of the MET ONE 237 particle counter.
3.2.5 Install the RH/T probe
To install the RH/T probe:
1. The RH/T probe is connected to the back of the unit (refer to Figure 6 on page 12,
item 1).
2. Attach the RH/T probe to the inlet so that the open end faces the direction of the air
stream.
Note: Make sure that the RH/T probe is attached before the counter is turned on.
3.3 Rear panel connections
The power switch, fuse holders and all connectors are on the rear panel of the counter as
shown in Figure 6 on page 12.
Note: The connectors for Analog Out and Printer appear only in models with the Analog Output
option, which do not have a built-in printer.
Figure 6 Rear panel connections
1RH/T probe connector 3Switch
2Optional connectors

13
Section 4 System Start Up
4.1 Power up
Turn on the switch at the back of the MET ONE 237 particle counter (refer to Figure 6 on
page 12). The counter will display the main screen when turned on (Figure 7 on page
15). If the LO BATT indicator is lit, plug in the AC adaptor to charge the battery. The
counter may be operated during the charging of the battery.
Note: Use the AC adapter provided by the manufacturer to charge the battery or operate the
counter. Other off-the-shelf power modules may have different power, current or polarity which could
damage the counter.

14
System Start Up

15
Section 5 Operation
The MET ONE 237 particle counter must be configured before operation for parameters
such as sample time and count alarm thresholds.
5.1 Front panel overview
The front panel of MET ONE 237 (refer to Figure 7) particle counter consists of:
•Status indicators—Show the current state of the counter
•Mode Key/Indicator—Shows the operating mode of the counter
•Display mode indicators—Show the current display mode
•LED display—3-digit display shows parameter and 7-digit display shows value
•Control keys—Used to operate the counter
Table 1 provides a description about indicators and key features or functions.
Figure 7 Front panel of the MET ONE 237 particle counter
1Status indicators 4Control keys
2Display mode indicators 5Mode keys
3LED display
Table 1 Indicators and key features or functions
Key Name Description
RUN/STOP Initiates a 6-second count cycle based on factory default settings. The red light in the
RUN portion lights and the pump starts operating.

16
Operation
5.2 Setup
The MET ONE 237 particle counter is ready to use when unpacked, but make sure that
the red sensor inlet cap is removed and the isokinetic probe is attached prior to sampling
(refer to section 3.2.1 on page 10). If the RH/T probe is used, attach it before the counter
is turned on.
5.3 Counting modes
The MET ONE 237 particle counter exhibits various counting modes—Manual mode,
Automatic mode, Concentration mode and Beep mode.
5.3.1 Manual mode
Note: The factory default setting for the counting mode is the Manual mode.
5.3.1.1 Factory default settings
Table 2 lists the default parameters that are programmed at the factory. The MET ONE
237 particle counter exhibits various counting modes. The factory default setting for the
counting mode will be the Manual mode..
DIFF Helps to operate the different settings of the counter.
SELECT
Helps to select the different settings of the counter. This is used to set the date and time,
enable the printer, change the sample period, set the alarm limits, set the number of
sampling cycles and so on.
PROG
Helps to program the different settings of the counter. This is used to program the date
and time, enable the printer, change the sample period, set the alarm limits, set the
number of sampling cycles and so on.
UP arrow
This is an adjustment key and it helps to navigate up in the choices available. It helps
scroll through the different sizes, the counter is programmed to monitor and view the
cumulative count in each size channel.
DOWN arrow
This is an adjustment key and it helps to navigate down in the choices available. It helps
scroll through the different sizes, the counter is programmed to monitor and view the
cumulative count in each size channel.
MODE Helps navigate and select the different counting modes of the counter.
Table 1 Indicators and key features or functions (continued)
Key Name Description
Table 2 Default parameter settings
Parameter Setting
Location number 000
Count mode Manual (the counter will take one sample and stop counting)
Alarm limits 0 (no particle count level alarms will be registered)
Channel 2 particle size 0.7 m in 227A; 0.5 m in 227B
Volume Liters (applies to Concentration mode only)
Temperature C (applies only if RH/T probe is attached).
RS232 mode Normal

17
Operation
In the Manual counting mode, the counter will take one sample of the programmed length
(default is 6-seconds) and stop. The CNT light will be lit in the display mode (refer to
Figure 7 on page 15, item 4). The particle sizes being monitored will be displayed in the
3-digit display and the actual cumulative counts will be displayed in the 7-digit display. For
example: 00.5 0000000.
Note: The MET ONE 237 particle counter is programmed to monitor several sizes, but only one size
is displayed at a time.
To view the particle sizes being monitored:
1. Press RUN/STOP to initiate a single 6-second count cycle based on the factory default
settings.
2. The red light in the RUN portion of the key will turn on.
3. The pump begins operation and after a short delay the COUNT light will turn on.
4. The COUNT light and the red light in the RUN portion of the key will turn off after the
pump finishes the 6-second sample.
5. Press the UP and DOWN arrow keys to view the different sizes.
6. The counter is programmed to monitor and view the cumulative count in each size
channel.
The MET ONE 237 particle counter operates at a sample flow rate of 0.1 cubic feet per
minute (cfm). Multiply the results of a 1-minute sample by ten to estimate the actual
particle count in a cubic foot of a sample.
Note: Parameters such as Change the sample period (refer to section 5.3.1.2 on page 17 ) and
Enable the printer (refer section 5.3.1.3 on page 18 ) are programmed in any order and at any time
the counter is not running, as long as the steps to set each parameter are followed.
5.3.1.2 Change the sample period
To change the sample period in the manual mode:
1. Press and hold the SELECT key until the PER light is lit and the 7-digit display shows
the current period setting in HH:MM:SS format, for example: 00:00:060.
2. Press and hold the PROG key. The light on the PROG key turns red. The HH digits
begin to flash.
3. Press and hold the SELECT key until the desired digits flash. Use the UP and DOWN
arrow keys to change the selected digits to the desired value.
4. Press and hold the PROG key to save the new settings and exit the programming
function. The digits will not flash now and the red light on the PROG key will turn off.
Baud rate 9600
Sample time 1 minute (length of sample period)
Hold time 1 second (hold time between samples in Automatic mode)
Program mode Unlocked (allows user programming).
Table 2 Default parameter settings (continued)
Parameter Setting