PP Systems EGM-4 User manual

EGM-4 Environmental Gas
Monitor For CO2
Operator’s Manual
Version 4.19
For Firmware (EPROM) Version 1.46 and Greater
© 2012 PP Systems. All Rights Reserved
14 February 2013
PP Systems
110 Haverhill Road, Suite 301
Amesbury, MA 01913 U.S.A.
Tel: [phone]
Fax: [phone]
Email: [e-mail]
Web Site: http://www.ppsystems.com

This page left intentionally blank for printing purposes.

Table of Contents
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Table of Contents
Table of Contents...........................................................................................3
Preface............................................................................................................5
System Calibration........................................................................................5
User Registration..........................................................................................5
Warning Notice...............................................................................................6
Condensation Risk........................................................................................6
PP Systems’ Contact Information .................................................................7
Technical Specification.................................................................................8
Introduction....................................................................................................9
Measurement Principle.................................................................................9
Getting Familiar With The EGM-4...............................................................10
Front Panel ................................................................................................................... 10
Environmental Sensor Inputs (I/O Ports) ....................................................12
Analog Output.............................................................................................13
Current Output............................................................................................13
RS232 Port.................................................................................................13
Soda Lime Absorber Column......................................................................13
Soda Lime ........................................................................................................................ 14
Keypad........................................................................................................14
LCD Display................................................................................................14
Gas Ports....................................................................................................14
Battery ........................................................................................................14
Powering The EGM-4 With Internal 12V NiMH Battery...............................14
CHARGING THE INTERNAL 12V NiMH BATTERY........................................................ 15
Charge Cycle and LED Indications for 12V NiMH Battery Charger................................. 15
Charge Socket............................................................................................15
Power Supply/Charger ..................................................................................................... 15
Power Switch..............................................................................................16
Operation......................................................................................................17
Main Menu..................................................................................................19
1REC..........................................................................................................19
Stand Alone CO2Analyzer (Probe Type 0)...................................................................... 20
Measurement Mode Display Structure............................................................................. 21
Changing Plot Number..................................................................................................... 22
Environmental Monitor (Probe Types 1-6 and 10)........................................................... 22
PP Systems Environmental Sensor Conversions:........................................................... 23
Steady State Porometer (Probe Type 7).......................................................................... 23
Closed System Soil Respiration (Probe Type 8).............................................................. 24
Use of our PAR Sensor with SRC-1 Soil Respiration Chamber ...................................... 24
Oxygen (Probe Type 9).................................................................................................... 27
Open System Soil Respiration (Probe Type 11).............................................................. 27
Calculation Of Fluxes For CFX And CPY Chambers....................................................... 29
2SET...........................................................................................................30
1EGM ............................................................................................................................... 30
Probe Types..................................................................................................................... 30
Probe Setting Override..................................................................................................... 31
2Z ..................................................................................................................................... 31
Changing the Zero Type................................................................................................... 31

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Changing the Zero Time................................................................................................... 32
3PMP................................................................................................................................ 32
Static Sampling with the EGM-4....................................................................................... 32
4AV................................................................................................................................... 32
5RECD ............................................................................................................................. 33
6ALM ................................................................................................................................ 33
Setting the Low CO2Alarm Setpoint................................................................................ 33
Setting the High CO2Alarm Setpoint ............................................................................... 34
7VOUT.............................................................................................................................. 34
3CAL...........................................................................................................35
Connecting Calibration Gas To The EGM-4 .................................................................... 35
4DMP..........................................................................................................36
Screen Display ................................................................................................................. 36
Data Dump ....................................................................................................................... 37
Transferring Stored Data Using The Windows®Based Software Program ..................... 37
Logging Data.................................................................................................................... 38
Record Structure .............................................................................................................. 38
Data Structure Based On Probe/Sensors........................................................................ 39
Error Cod.......................................................................................................................... 40
es...................................................................................................................................... 40
EGM Serial Outputs....................................................................................41
5CLR...........................................................................................................41
6CLK...........................................................................................................42
Diagnostics and Initialisation .....................................................................43
Diagnostics .................................................................................................43
Initialisation.................................................................................................43
Maintenance.................................................................................................44
Soda Lime Absorber Column......................................................................44
Soda Lime ........................................................................................................................ 44
MATERIAL SAFETY DATA FOR SODA LIME ................................................................ 45
Servicing The EGM-4..................................................................................46
Fuse.................................................................................................................................. 46
Inside the EGM-4.......................................................................................................... 47
Infrared Source................................................................................................................. 47
Checking EGM-4 Raw A/D Readings .............................................................................. 48
EPROM ............................................................................................................................ 48
ZERO Valve...................................................................................................................... 49
12V Lead Acid Battery...................................................................................................... 49
12V Lead Acid Battery Specification................................................................................ 49
Removing The 12V Lead Acid Battery............................................................................. 49
12V NiMH Battery............................................................................................................. 50
12V NiMH Battery Specification....................................................................................... 50
Removing The 12V NiMH Battery.................................................................................... 50
Air Sampling Pump........................................................................................................... 51
Replacing The Air Sampling Pump .................................................................................. 51
Cleaning The Air Sampling Pump.................................................................................... 51
In-Line Filter Assembly (Hydrophobic)............................................................................. 52
Consumables and Spares for EGM-4.........................................................53
User Notes....................................................................................................54

Preface
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Preface
It is extremely important that you take the time to review this operator’s manual prior to
installation and operation of the EGM-4 CO2Gas Analyzer. Otherwise, damage may be
caused which is not covered under our normal warranty policy. This operator’s manual is
relevant to all EGM-4’s running firmware (EPROM) version 1.30 and higher.
System Calibration
•This product is shipped as a factory calibrated system. System calibration is not
required upon receipt from our factory.
•Familiarization with the documentation and calibration procedures is required prior to
future recalibration. See section 3CAL on page 35 of this manual.
•All calibration related questions may be directed directly to PP Systems at:
Telephone: [phone]
Fax: [phone]
Email: [e-mail]
User Registration
It is very important that ALL new customers register with us to ensure that our user’s list is
kept up to date. If you are a PP Systems’ user, please register yourself electronically on our
web site at http://www.ppsystems.com/user_registration2.htm .
Only REGISTERED users will be allowed access to our protected “Users” section of our web
site. This section will contain important product information including hardware/software
updates, application notes, newsletters, etc.
Thank you in advance for your cooperation.
The warranty excludes all defects in equipment
caused by incorrect installation, operation or
maintenance, misuse, alteration, and/or
accident.

Warning Notice
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Warning Notice
This instrument must not be used in situations where its failure could result in injury or
death. For applications where failure of this instrument to function correctly would
lead to consequential damage, the Analyzer must be checked for correct operation and
calibration at intervals appropriate to the criticality of the situation.
This manual is provided to help you install and operate the equipment. Every effort has been
made to ensure that the information contained in this manual is accurate and complete. PP
Systems does not accept any liability for losses or damages resulting from the use of this
information. PP Systems' equipment warranty is limited to replacement of defective
components, and does not cover injury to persons or property or other consequential
damage. This manual, and the information contained in it, is copyright to PP Systems. No
part of the manual may be copied, stored, transmitted or reproduced in any way or by any
means including, but not limited to, photocopying, photography, magnetic or other mechanical
or electrical means, without the prior written consent of PP Systems.
The EGM-4 is covered under warranty for one complete year, parts and labour included.
This, of course, is provided that the equipment is properly installed, operated and maintained
in accordance with written instructions (i.e. Operator's Manual). The warranty excludes all
defects in equipment caused by incorrect installation, operation or maintenance,
misuse, alteration, and/or accident.
If for some reason, a fault is covered under warranty, it is the responsibility of the customer to
return the goods to PP Systems or an authorised agent for repair or replacement of the
defective part(s).
Condensation Risk
If condensation occurs in the analysis sample line, free water may enter the analyzer causing
serious damage which will result in a very expensive repair. Therefore, it is critical that you
periodically inspect the pipeline to be sure that condensed water does not enter the analyzer.
If the EGM-4 is supplied on its own, we do NOT supply any external filters. If the EGM-4
is used in conditions where there is risk of condensation or water in the sample line, (i.e.
when used with the SRC-1, CPY-2, CPY-4 or CPY-3 chambers for measurement of
soil/canopy assimilation, we strongly recommend fitting our hydrophobic filter to the “Gas In”
port as shown below. Our hydrophobic filter assembly (Part No. 10045-1) is supplied with all
SRC-1’s, CPY-2’s, CPY-4’s and CPY-3’s. All EGM-4 customers can purchase this filter from
PP Systems (Part No. 10045-1) at any time if required. In addition, when this filter is used, it
must be checked regularly and replaced as when dirty or wet. Otherwise, blockage can
occur.
Our in-line filter assembly
(Part No. 10045-1)

Warning Notice
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For maintenance instructions, see In-Line Filter Assembly (Hydrophobic) on page 52.
Very Important
If there is any risk of of water entering the EGM-4, you must protect the instrument by using
an external 3 µm hydrophobic filter (Part No. 10045-1) or water drop out trap. We strongly
recommend using 3 µm filters as any other size may cause damage to the pump. If a
water drop out trap is used, it should be regularly checked and emptied as required.
If condensation persists, it is then recommended that a PP Systems’ water vapor equilibrator
(Part No. 10049-1) is used (see picture below). This is constructed from a material that is
very permeable to water vapor but impervious to CO2. If this is placed in-line in the analysis
pipe at the sampling point, the water vapor concentration of the analysis air will be brought
close to ambient.
Part No. 10049-1 Water Vapor Equilibrator fitted to top of EGM-4
The problem may also be avoided by putting a suitable water drop out trap or drier in the
same position. Drierite (anhydrous Calcium Sulphate) is suitable. DO NOT use Silica Gel,
which also absorbs CO2.
Please note that any method used to remove excess water from the analysis
sample will render any humidity measurement incorrect.
If you have any questions whatsoever with regards to possible condensation risk,
contact PP Systems (See PP Systems’ Contact Information on page 7).
PP Systems’ Contact Information
PP Systems
110 Haverhill Road, Suite 301
Amesbury, MA 01913 U.S.A.
Tel: [phone] Fax: [phone]
Support: [e-mail]
Sales: [e-mail]
Service: [e-mail]

Technical Specification
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Web Site: http://www.ppsystems.com
Technical Specification
Analysis Method
Non-dispersive infrared with microprocessor control and linearisation.
Measurement
Range
(CO2)
0-1,000 ppm (µmol mol-1)
0-2,000 ppm (µmol mol-1)
0-5,000 ppm (µmol mol-1)
0-10,000 ppm (µmol mol-1)
0-20,000 ppm (µmol mol-1)
0-30,000 ppm (µmol mol-1)
0-50,000 ppm (µmol mol-1)
0-100,000 ppm (µmol mol-1)
Measurements are automatically corrected for temperature and pressure.
Accuracy (CO
2
)
< 1% of span concentration over the calibrated range, but limited by the
accuracy of the calibration gas mixture.
Linearity
< 1% throughout the range.
Stability
Automatic Zero at regular intervals. It corrects for sample cell
contamination, source and detector ageing and pre-amplifier gain
changes.
Sample Pump
Integral DC pump operating at a flow rate of approximately 350 ml/min.
Pump can be disabled for static measurements on demand.
Gas Flow Rate
Through Analyzer
Minimum flow rate: 200 ml/min
Maximum flow rate: 400 ml/min
Environmental
Sensor Interface
Two inputs available for use with external sensors (humidity, temperature,
PAR, oxygen, soil respiration, canopy assimilation, etc.).
Air Filter
Filtered sample line (hydrophobic)
Calibration
Default value preset in factory (Built-in Initialization). Automatic
calibration via keypad if required.
CO2Control
High and low set points
Alarm
Audio Alarm
Real Time Clock
Accuracy > 1 minute per month at 25˚C, operating temperature 0-70˚C.
Automatic correction for month end and leap years.
Recording
Manual (by keypress) or automatic at user selected intervals between 1
and 250 minutes.
Keypad
Custom, tactile keypad
Data Storage
512 K Battery backed RAM (1,000 records).
Response Time
Display/analog output: 1.6 seconds
Analog Output
(CO2only)
4-20 mA, 0-1 V, 0-2 V, 0-3 V, 0-4 V, 0-5 V (Linear)
Digital Output
(RS232)
9600 baud/8 data bits, 1 start bit/2stop bits/no parity
ASCII Format
Display
High contrast 2 x 16 character LCD.
Power Supply
12 V, 2.0 Ah Rechargeable Lead Acid Battery providing up to 4 hours
continuous use or 12V NiMH rechargeable battery providing up to 8 hours
continuous use. Longer times available with external 12V battery. Battery
life may be reduced when EGM-4 is used with add-on
sensors/accessories.
Gas Connections
Two barbed fittings (inlet and exhaust) for 1/8” (.125”) ID tubing.
Housing
High impact, aluminum enclosure.
Operating
Environment
-5oC – 50o C, non-condensing. In dirty or high humidity environments,
external air filtration is required.
Dimensions
18 cm (W) x 21.5 cm (H) x 6.3 cm (D)
Weight
1.9 kg

Introduction
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PP Systems is continuously updating its products and reserves the right to amend product
specifications without notice.
Introduction
The EGM-4 CO2Analyzer is a portable operated unit that is powered by an internal 12 V, 2.0
Ah lead acid rechargeable battery providing up to 4 hours continuous use or 12V NiMH
rechargeable battery providing up to 8 hours continuous use. For extended operation in the
field, PP Systems can also provide an external power supply cable that will allow you to
connect up to an external 12 V battery. If interested, please contact PP Systems (See PP
Systems’ Contact Information on page 7).
The EGM-4 is a high precision instrument for use in CO2monitoring applications such as
greenhouses, environment control rooms, nurseries and laboratories. Long term stability and
accuracy is ensured as a result of our unique “Auto-Zero” technology. The EGM-4 also
features inputs for additional sensors for measurement of humidity, temperature, PAR, O2,
soil respiration, soil temperature and canopy assimilation.
Measurement Principle
The EGM-4 CO2is a non-dispersive, infrared gas analyzer that features an “Auto-Zero”
facility. Using infra-red gas analysis techniques, we can readily determine CO2(Carbon
Dioxide) concentrations to within a few ppm and instantaneous measurements are possible.
Gases with di-atomic molecules such as CO2strongly absorbs photons in the infra-red range.
For CO2 , one region of strong absorption is 4.26 microns. A source emitting strongly at this
wavelength is a light bulb. If this is positioned at one end of a tube and at the other end is
placed a sensor that is sensitive to photons at 4.26 microns, we have a simple infra-red gas
Analyzer. As carbon dioxide is passed down the sample cell, it absorbs some of the infra-red
and the sensor reading decreases. The “Auto-Zero” feature, which occurs at regular
intervals, allows for fast warm-up, adaptation to changing ambient conditions and excellent
stability of the CO2signal. The action of auto-zeroing minimizes the effects on span (gas
sensitivity) of sample cell contamination, source aging, changes in detector sensitivity and
changes in pre-amplifier gain.
The entire optical bench assembly (i.e. sample cell) is filtered and should never require
replacement.
To ensure proper operation, the EGM-4 MUST always
be operated in a vertical, upright position.
The EGM-4 can be supplied with two different optical benches. One bench is optimized for
measurement of CO2in the ranges of 0-1,000 ppm up to 0-30,000 ppm. The other optical
bench is optimized for 0-50,000 ppm and 0-100,000 ppm. All instruments are checked and
calibrated at the concentration specified at time of order to ensure that the readings are < 1%
of that value. When an instrument is reset to its default values (i.e. when the system is
initialised, see Initialisation on page 43), it returns to this setting.
It is important to note that the information contained in this documentation normally
refers to the latest firmware (EPROM) which can change over time. We recommend
that all users keep in contact with us from time to time to ensure that they are running
the most up to date system firmware.

Getting Familiar With The EGM-4
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Getting Familiar With The EGM-4
Front Panel
Figure 1 EGM-4 Display (Front Panel)
LCD Display
(2 x 16)
Character
Custom,
tactile
keypad
Sensor I/O
Connectors
RS232
Connector
Gas In Port
Gas Out Port
4-20 mA
Access Hole

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Top of EGM-4
Back Panel of EGM-4 fitted with 12V Lead Acid Battery
Back panel of EGM-4 fitted with 12V NiMH Battery

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Environmental Sensor Inputs (I/O Ports)
The EGM-4 has 2 environmental sensor inputs (I/O) to allow external sensors (i.e. soil
respiration chamber, CPY-2/CPY-3/CPY-4 Canopy Assimilation Chambers, TRP-1
Temperature/PAR Probe, PAR-1 Probe, etc.) to be used simultaneously. All sensor inputs
lines require 0-1V input. Note, the sensor inputs are displayed in mV (i.e. 0-1,000 mV)
instead of Volts.
If one of our environmental sensors is used with the EGM-4, it must be plugged into the
instrument prior to turning it on. The EGM-4 automatically detects the sensor connected as a
result of code resistors which are fitted to the 15 pin D Connector between pins 1 and 6. The
code resistors for our environmental sensors are as follows:
Probe Type
PP Systems Sensor
Code Resistor
0
The EGM-4 is being used as a stand
alone IRGA (no external sensors
connected)
Not applicable. This is
determined by keypad
selection.
1
STP-1 Soil Temperature Probe
100 KΩ
2
Not Applicable. Used to be used with
older sensors.
56 KΩ
3
TRP-1/TRP-2 Temperature/PAR Probe
36 KΩ
4
PAR-1/PAR Sensor
27 KΩ
5
Not Applicable. Used to be used with
older sensors.
20 KΩ
6
Not Applicable. Used to be used with
older sensors.
15 KΩ
7
Steady State Porometer (PMR-5)
Not applicable. This is
determined by keypad
selection.
8
SRC-1 Soil Respiration Chamber or CPY-
2/CPY-
4 Canopy Assmiliation Chamber
(Closed System operation)
9.1 KΩ
9
OP-1/OP-2 O2 Sensor
20 KΩ
10
Not Applicable. Used to be used with
older sensors.
5.6 KΩ
11
CFX-1 Open System Soil Respiration
Chamber or CPY-3 Canopy Chamber.
4.3 KΩ
12
CPY-4 Canopy Assimilation Chamber
(Closed System Operation)
9.1 KΩ
Note. When the EGM-4 is supplied with a PP Systems accessory (i.e. SRC-1, CPY-4, etc.),
the probe type will be set at the factory based on the accessory supplied. Therefore, it may
be necessary to change the probe type if required. The probe type can be changed from the
2SET menu on page 30. if required. See Analog Output on page 13 for analog output pin-
outs and location for code resistor placement (Pin 1).

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Analog Output
The EGM-4 has two 15 pin I/O connectors with a 0-5V analog output. The default output is
set at 0-5V. However, this can be changed by the user (if required) to any value in between
(i.e. 0-1V, 0-2V, 0-3V, 0-4V). (See 7VOUT on page 34). The pin-outs for the two I/O
connectors are as follows:
DB15 I/O
Connector
Description
1
Code Resistor (connect to pin 6)
2
PAR
3
RH
4
Aux. Analog Input
5
Temp
6
+5V
7
Alarm 1 (Buffered)
8
Digital Ground
9
RS232 Output
10
Data Request /CO2 Control
11
RS232 Input
12
+12V
13
Aux. Digital I/O
14
CO2Analog Out
15
Analog Ground
Current Output
If required, current output (4-20 mA) is available and can be accessed through the top of the
EGM-4. Inside the EGM-4, there is a 2 pin connector labelled CN7 on the PC075-1 circuit
board. The EGM-4 contains a 4-20 mA current transmitter that is powered from an internal
12V supply. To utilize the current output, simply connect the Iout pins directly to a 4-20 mA
meter or digitizer. No power supply or other connections are required to get a 4-20 mA output
from the EGM-4. Applying voltage to the Iout pins higher than 12 V will damage the internal
circuitry.
RS232 Port
The EGM-4 has one 9 pin RS232 connector used for transferring stored data to a PC or
laptop computer. To transfer stored data from the EGM-4 to an external PC, connect the data
transfer cable (supplied by PP Systems) between the RS232 connector on the EGM-4 and
the 9 pin serial connector on the PC. Data transfer software (supplied by PP Systems) steps
you through the data transfer process. See Data Dump on page 37 for more information on
data transfer. If required, a data transfer cable can easily be made up by the user. See table
below:
9 PIN D Socket on
EGM-4
9 Pin D Socket on PC
Pin 2
Pin 2
Pin 5
Pin 5
Soda Lime Absorber Column
The absorber column is labelled “Soda Lime” on the rear panel. It contains a CO2scrubbing
desiccant known as Soda Lime. When air passes through this column, it removes all of the
CO2from the air stream. The “Auto-Zero” facility built into the EGM-4 periodically switches
the flow of gas from the Analyzer through this column to check the Analyzer zero. This
routine ensures long term stability and accuracy of the CO2Analyzer. It automatically

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corrects for such things as sample cell contamination, source aging, detector sensitivity and
changes in electronics.
Soda Lime
Soda lime is used to remove CO2from air entering the EGM-4. It is supplied as self-
indicating granules (1-2.5mm) that turn from green to brown as it becomes exhausted. The
contents of the absorber column should be replaced when it is 2/3rds exhausted (brown).
Soda Lime cannot be regenerated and should be discarded when exhausted. For accurate
measurements and calibration, it is absolutely critical that the EGM-4 absorber column is not
exhausted. If the soda lime is becoming exhausted, it will cause the ZERO to be performed
on non-ZERO air causing an error in the calibration.
When exhausted, the Soda Lime Cap should be removed along with the foam filter pad (with
the EGM-4 facing upwards) and the contents discarded. When replacing the soda lime, we
recommend using a funnel to ensure that the desiccant fills the absorber column. Leave
approximately 1” from the end of the column to allow the foam pad and cap to be refitted.
! CAUTION !
WASH YOUR HANDS AFTER HANDLING SODA LIME
Keypad
The custom, tactile keypad consists of 12 keys. There are ten keys that are labelled 0-9.
Also, there are a few keys that have additional functions. The Y/R (Yes/Record) key is used
to accept settings and to record measurements. In addition, the Y/R key is pressed to
advance from one display to the next. The Nkey is normally used to return to the Main Menu
from Measurement Mode, reject settings or to step back through the menus. The 8/X key is
used to toggle from one display to another in Measurement Mode.
LCD Display
The EGM-4 features a 2x16 character, backlit LCD display.
Gas Ports
There are two barb fittings located on the top of the EGM-4. Each barb fitting is designed for
use with 1/8” (.125”) ID tubing. One barb fitting is labelled “Gas In” and the other “Gas Out”.
The sampling line should be fitted to the “Gas In” port using 1/8” tubing. The “Gas Out” line
should be left open to atmosphere to allow the sample air to exhaust without restriction. Note,
for closed system measurements with our SRC-1 Soil Respiration Chamber or CPY-2 Canopy
Asssimilaton Chamber, one gas line is connected to the “Gas In” port and the other to the
“Gas Out” port.
Battery
The EGM-4 can be powered by an internal 12V 2.0 Ah lead acid rechargeable battery
providing up to 4 hours continuous use or a 12V NiMH rechargeable battery providing up to 8
hours continuous use.
Powering The EGM-4 With Internal 12V NiMH Battery
There are two ways to power the EGM-4 :-
1. Using the internal 12V NiMH battery:

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A. Set the slide switch on the rear panel of the EGM-4 to the 'BATTERY'
position.
B. Switch the instrument on using the 'POWER' toggle switch.
Note, the internal battery CANNOT be used to power the EGM-4 while it is being
charged, but the external power supply can be used simultaneously instead.
2. Using the external power supply
A. Set the slide switch on the rear panel of the EGM-4 to the 'CHARGE' position.
B. Plug the EGM-4 External Power Supply into the '-ve/+ve' socket.
C. Switch the instrument on using the 'POWER' toggle switch.
CHARGING THE INTERNAL 12V NiMH BATTERY
1. Set the slide switch on the rear panel of the EGM-4 to the 'CHARGE' position.
2. Plug the EGM-4 NiMH Battery Charger into the 'CHARGE SKT'. To do this, line up
the three socket pins with the plug, and screw on the plug sleeve (do not overtighten).
Charge Cycle and LED Indications for 12V NiMH Battery Charger
LED
Mode
Orange
Battery not connected
Orange
Battery initialization & analysis
Red
Fast charge
Green with intermittent orange flash
Top-off charge
Green
Trickle charge
Alternating red-green
Error
Check to make sure that the “charge indicator light" (red LED) on the charger is a steady state
red after connection. If the LED does not come on, or it fluctuates, then there may be a bad
connection.
WARNING
THE EGM-4 IS FITTED WITH A SLIDE SWITCH (CHARGE BATTERY).
DO NOT OPERATE THE SLIDE SWITCH WHEN THE EGM-4 IS
CONNECTED TO ANY EXTERNAL POWER SUPPLY OR BATTERY
CHARGER.
Charge Socket
The charge socket is labelled “12V DC” on the rear panel of the EGM-4. The AC
Adapter/charger supplied by PP Systems plugs into this socket to charge the internal 12V 2.0
Ah lead acid battery.
Power Supply/Charger
All systems are supplied complete with an AC Adapter/Charger designed specifically for use
with the EGM-4 for charging the internal 12 V 2.0 Ah lead acid battery and for continuous
operation in the lab. This unit has the following technical specification:
Input
100-240 V ~ 50-60 Hz

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Output
15 V @ 2.7 A
Power Indicator
Green LED
Dimensions
10.5 cm x 6.5 cm x 4.5 cm
Weight
0.3 kg
!!! WARNING !!!
USE OF POWER SUPPLIES AND BATTERY CHARGERS OTHER THAN
THOSE SUPPLIED BY PP SYSTEMS FOR THE EGM-4 WILL INVALIDATE
THE WARRANTY.
Please note. EGM-4’s can also be powered by an internal, rechargeable 12V NiMH battery
for extended operation in the field. For more information on this option, refer to Powering The
EGM-4 With Internal 12V NiMH Battery on page 14.
Power Switch
To power up the EGM-4, the On/Off Switch should be toggled to the “On” position. To turn
the instrument off, the switch should be toggled to the “Off” position.

Operation
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Operation
The EGM-4 is a menu driven instrument. Note. If any external sensors/probes are to be
used with the EGM-4, they MUST be electrically connected to one (or both) of the I/O
ports prior to turning the instrument on. When the instrument is first powered up, it will go
through its normal warm-up period that takes approximately 5 minutes. Immediately after
powering up the system, the following is displayed:
Whereas:
EGML
Or
EGMH
Or
PMR
Refers to an EGM-4 with a measurement range up to 30,000
ppm.
Refers to an EGM-4 with a measurement range of 50,000 or
99,999 ppm.
Refers to PMR-5 Steady State Poromter.
0456
Refers to the serial number of the EGM-4
V1.30
Refers to the firmware (EPROM).
During warm-up, there is a delay of approximately 45 seconds to allow for calibration of the
electronics and then the instrument proceeds to warm-up until the Analyzer temperature
reaches 50 ˚C. A final Zero check is then performed before proceeding to the Main Menu.
Also during warm-up, several system checks are performed. The “Checksum” message is set
to a factory default value of 123456. If this is incorrect as when a new version of firmware is
first installed, a “CHECKSUM ERROR SEE MANUAL” message is displayed. If this occurs,
simply press any key to proceed to the Main Menu. From the Main Menu, press key 0 to re-
initialise the system (See Initialisation on page 43).
The next display will be dependent on whether or not any external sensors are being used
with the EGM-4.
If the EGM-4 is being used on its own, the following will be displayed:
Where:
C2000
Corresponds to the last calibration gas concentration. After DEFAULT, it is the
original range specified by the end user.
1V=2000
Range of the voltage signal corresponding to the CO2concentration.
R150
Number of records stored in memory.
If the EGM-4 is being used with an external sensor (i.e. SRC-1 Soil Respiration Chamber),
the following will be displayed:
PP SYSTEMS C2002
EGML 0456 V1.30
C2000 1V=2000
mV INPUTS R150
C2000 5V=2000
PROBETYPE 8 R150

Operation
EGM-4 Operator's Manual – Version 4.19
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Where:
C2000
Corresponds to the last calibration gas concentration. After DEFAULT, it is
the original range specified by the end user.
5V=2000
Range of the voltage signal corresponding to the CO2concentration.
PROBETYPE 8
Refers to the probe/sensor connected to the EGM-4. For a list of probe
types, see Environmental Sensor Inputs (I/O Ports) on page 12.
R150
Number of records stored in memory.
If the EGM-4 is being used as a porometer (i.e. PMR-5), the following will be displayed:
Where:
C2000
Corresponds to the last calibration gas concentration. After DEFAULT, it is
the original range specified by the end user.
5V=2000
Range of the voltage signal corresponding to the CO2concentration.
POROMETER
Refers to the PMR-5.
R150
Number of records stored in memory.
After all system checks have been performed and the system achieves warm-up, the EGM-4
Main Menu is displayed as follows:
Note. If the instrument was just powered up, the display will show “WARM UP DELAY
TEMPERATURE = XX” until the instrument achieves its warm up temperature of 50 ˚C prior
to the Main Menu.
While in Measurement Mode, the following key presses can be performed:
Key
To:
Z/0
Perform a manual Zero.
Y/R
Record a measurement and place it in memory.
8/X
Changes to a different display (See section 1REC).
N
Return to the Main Menu.
Refer to the following sections for more information on menus and displays.
1REC 2SET 3CAL
4DMP 5CLR 6CLK
C2000 5V=2000
POROMETER R150

Operation
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Main Menu
There are 6 options available to the user when the Main Menu is displayed as follows:
Where:
Press
Key
To
1
Go Into Measurement Mode. See 1REC on page 19.
2
Change system settings (i.e. zero type and time interval, recording type, alarm
settings, etc.). See 2SET on page 30.
3
To calibrate the Analyzer. See 3CAL on page 35.
4
To dump stored data to a PC or to view data on the LCD display. See 4DMP on
page 36.
5
Clear system memory. See 5CLR on page 41.
6
Set/check the system clock (date and time). See 6CLK on page 42.
Each option is discussed in further detail below.
1REC
To begin recording, press key 1. Please note, the EGM-4 display is dependent upon which
probe type is connected to it. The following table illustrates the Probe Types:
If the EGM-4 is used as a:
Then The
Probe Type is
set to:
Stand Alone CO
2
Analyzer (including optional humidity sensor
is fitted). See Stand Alone CO2 Analyzer (Probe Type 0) on
page 20.
0
Environmental Monitor
(With one of our Environmental Sensors such as %RH,
temperature, PAR, O2, etc.). See
Environmental Monitor
(Probe Types 1-6 and 10) on page 22.
1-5
Steady State Porometer. See Steady State Porometer (Probe
Type 7) on page 23.
7
Closed System Soil Respiration
(i.e. SRC-1 Soil Respiration Chamber). See Closed System
Soil Respiration (Probe Type 8) on page 24.
8
O2 probe
9
RH and Temperature
10
Open System Measurement
(i.e. CFX-1 Soil Respiration Chamber, CPY-3 Chamber). See
Open System Soil Respiration (Probe Type 11) on page 27.
11
Closed System operation with the CPY-4. See Closed System
Soil Respiration (Probe Type 8) on page 24.
12
Important Note. Most instruments are supplied with the probe type already set if a sensor is
supplied with the EGM-4. If an existing EGM-4 user purchases an environmental sensor from
us, it may be necessary to set the probe type (see 1EGM on page 30).
In the followng sections, some displays will vary slightly to what is discussed
depending on firmware and sensors connected to the EGM-4.
1REC 2SET 3CAL
4DMP 5CLR 6CLK

Operation
EGM-4 Operator's Manual – Version 4.19
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Stand Alone CO2Analyzer (Probe Type 0)
To begin recording, press key 1. Immediately after pressing key 1, the instrument will
automatically perform a zero check. Once completed and assuming no problems with the
zero, the instrument will proceed to “Measurement Mode” where the CO2value (plus
additional values if optional humidity sensor is present) being measured by the instrument is
displayed as follows:
Where:
C
CO2concentration (ppm)
H
Humidity (mb). Only if optional %RH/Temp sensor is present.
A
Absolute pressure in sample cell (mb).
P
Refers to probe type. See 1REC on page 19.
To return to the Main Menu while in Measurement Mode, simply press the N key.
Note. If the instrument was just powered up, the display will show “WARM UP DELAY
TEMPERATURE = XX” until the instrument achieves its warm up temperature of 50 oC prior
to entering into Measurement Mode.
Additional information (i.e. external sensors, etc.) may be viewed on the LCD display if
required. While in Measurement Mode with the CO2concentration displayed, subsequent
presses of the 8 key will show additional displays as follows:
C 545
A1011 P00
C 545 H11.2
A1011 P00
Display 1A (without optional %RH
Sensor)
Display 1B (with optional humidity
Sensor)