RAEGuard PID FGM-1000 Series - Photoionization Detector Transmitter - Operation & Maintenance Manual
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RAEGuard PID
FGM-1000 Series
Photoionization Detector Transmitter
Operation & Maintenance Manual
p/n 033-4001-001 Rev B
READ BEFORE OPERATING
This manual must be carefully read by all individuals who have or
will have the responsibility of using, maintaining, or servicing this
product. The product will perform as designed only if it is used,
maintained, and serviced in accordance with the manufacturer’s
instructions.
CAUTION
To reduce the risk of electric shock, turn off power before remov-
ing the lamp housing cap and PID sensor for service. The lamp
housing cap provides an electrostatic shield. Never operate the
unit when the cap is removed. Remove the lamp housing cap and
sensor block only in an area known to be NON-HAZARDOUS.
WARNING!
The calibration of all newly purchased RAE Systems instruments
should be tested by exposing the sensor(s) to known concentration
calibration gas before the instrument is used or put into service.
For maximum safety, the accuracy of the RAEGuard PID should
be checked by exposing the sensor(s) to known concentration cali-
bration gas.
AVERTISSEMENT!
La calibration de toute instruments de RAE Systems doivent être
teste en exposant l’instrument a une concentration de gaz con-
nue par une procédure dietalonnage avant de mettre en service
l’instrument pour la première fois. Pour une sécurité maximale,
la sensibilité du RAEGuard PID doit être verfier en exposant
l’instrument à une concentration de gaz connue par une procédure
dietalonnage.
Contents
1. General Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Hazardous Location Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Operation of RAEGuard PID. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Physical Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Installation and Access Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . 6
Instrument Assembly Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Electrical Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Instrument Assembly Instalation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Sample Gas Plumbing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Display and Alarm Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
System Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Reading Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Alarm Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Access to Programming Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4 Programming Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.5 Calibration Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Zero Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Span Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.6 Correction Factors for Other Gases . . . . . . . . . . . . . . . . . . . . . . . . . 16
Programming the Correction Factor . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Modifying the Span Gas Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Manual Conversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.7 Calibration With Other Compounds. . . . . . . . . . . . . . . . . . . . . . . . . 17
2.8 4-20 mA Current Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.9 Duty Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3. Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4. Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1 Cleaning the PID Sensor and Lamp. . . . . . . . . . . . . . . . . . . . . . . . . 21
4.2 Pump Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3 Filter Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5. Troubleshooting Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Appendix A: Correction Factors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Appendix B: Maximum Reading Capabilities and Indications . . . . . . . 29
Appendix C: Limited Product Warranty. . . . . . . . . . . . . . . . . . . . . . . . . 30
Appendix D: RAE Systems Contacts. . . . . . . . . . . . . . . . . . . . . . . . . . . 31
www.raesystems.com 1
1. General Information
The RAEGuard PID is a fixed photoionization detector (PID) that mea-
sures a broad range of volatile organic compounds (VOCs). It operates
on 9-36 VDC and provides an analog (4-20 mA) signal output in three
ranges of 0.01 - 20.00 ppm, 0.1-100.0 ppm, and 1-1000 ppm isobutylene
equivalent. Housed in an explosion-proof enclosure, the RAEGuard PID
is equipped with a local digital display of the gas concentration and func-
tion keys for performing calibration. This flow-through sampling unit is
ideal for remote sampling.
Key Features
• 4-20 mA analog output
• Resolution of 0.01 ppm for precision model (range to 20 ppm)
• Explosion-proof enclosure for hazardous environment applications
• Magnetic key interface eliminates need to open explosion-proof
enclosure when making operation parameter adjustments
• Long-life 10.6 eV ultraviolet lamp with 3D sensor
• Can draw sample from up to 100 feet (30 meters)
• Sampling pump duty cycling for lamp self-cleaning
• LCD and status/error LEDs
• Operation at 9 to 36 VDC
• Two dry contacts (
Specifications
Size 5.0" L x 5.0" W x 4.5" H
127 mm x 127 mm x 115 mm
Weight 5.5 lbs (2.5 kg)
Detector 3D PID sensor std. 10.6 eV lamp
Calibration 2-point field calibration
Enclosure Rating US & Canada: UL, cUL Class I, Division
1 & 2, Groups B, C, D
Europe: 0575 II 2 G
Demko 03 ATEX 0229512
EEx d IIB T6
Power 9 to 36 VDC max. 125 mA at 24V
Output 4-20 mA w/12V compliance at 24V
Sampling Internal diaphragm pump, >500 cc/min
Sampling Distance 100 feet (30 meters) maximum
Display 7-segment, 4-digit screen with 4 color-
coded alarm LEDs
Response Time 40 seconds to 90% of reading using isobu-
tylene and 40% duty cycle
User Interface Magnetically accessed keys for calibration
Temperature -20º C to 55° C (-4º F to 131° F)
Humidity 0-95% relative humidity (non-condensing)
Dry Contacts High and low alarm levels Max 30V, 2A
each
Mounting 2 holes, 5.25" (133 mm) from center to
center
Ranges 0.01 - 20.00 ppm, 0.1 - 100.0 ppm, and
(isobutylene equivalent) 1 - 1000 ppm
(Ranges are different product models, and
not user-selectable when operating unit.)
This product may be covered by one or more of the following U.S. Patents:
5,393,979 5,561,344 5,773,833 6,225,633
6,313,638 6,333,632 6,320,388
www.raesystems.com 3
2. Operation of RAEGuard PID
The RAEGuard PID photoionization detector transmitter consists of a
UV light source, a detection chamber, a sample draw pump, and associat-
ed electronic driver and measurement circuits. The contents of the Lamp
Cleaning Kit (part number 081-0002-000) include: lamp cleaner, swabs,
finger cots, and lens paper. The contents of the Accessory Kit (part num-
ber 033-0912-000) include: sensor puller, Magnet Key, and screwdriver.
Prior to factory shipment, the RAEGuard PID is calibrated and tested
using isobutylene gas.
The calibration of all newly purchased RAE Systems instruments should be
tested by exposing the sensor(s) to a known concentration calibration gas
before the instrument is put into service for the first time. For maximum
safety, the accuracy of the RAEGuard PID should be checked at least
monthly when operated in a relatively clean environment. However, in a less
clean, highly humid, or variable environment, it may require more frequent
(such as once a week) accuracy checks for optimal performance. Recalibrate
the unit if readings are outside the limits defined by the user.
RAE Systems recommends the following procedure, based on the ISEA
(Industrial Safety Equipment Association) protocol, to establish the interval
between verification checks:
1. The protocol defines the difference between a functional (bump) test
and a full calibration. A functional (bump) test is defined as a means
of verifying calibration by using a known concentration of test gas
to demonstrate that an instrument’s response to the test gas is within
acceptable limits. A full calibration is defined as the adjustment of an
instrument’s response to match a desired value compared to a known
concentration of test gas as defined in section 2.5 of this manual.
2. During a period of initial use in the intended atmosphere, perform
a daily functional (bump) test to ensure there is nothing degrading
sensor performance. The period of initial use must be of sufficient
duration to ensure that the sensor is exposed to all conditions that
might have an adverse effect.
3. Any instrument that fails a functional (bump) test must be adjusted
by means of a full calibration procedure before further use.
4. If the tests demonstrate that it is not necessary to make adjustments,
then the time interval between checks may be lengthened. For
maximum safety, this interval should not exceed 30 days.
4 RAEGuard PID
2.1 Physical Description
Physical Dimensions
The design of RAEGuard PID allows it to be easily mounted and inter-
faced with a fixed-point gas monitoring system. The detector transmitter is
housed in a 5.0" L x 5.0" W x 4.5" H (127 mm x 127 mm x 115 mm) explo-
sion-proof case with two holes 5.25" (133 mm) apart from center to center.
3/4" - 14 NPT 3" [127.00] 3/4" - 14 NPT
4.90" [124.46]
ZERO SPAN
OK FAULT LOW HIGH
O 5/16"
+ MODE -
O 4 1/2" [114.30] 3/4" - 14 NPT 1.08" [27.43]
5 1/4" [133.35] 4.60" [116.84]
RAEGuard PID Standard Version Installation.
Sample Gas Flow
The RAEGuard PID has an internal diaphragm pump that pulls the
sample gas in and forces it out through its outlet. The gas is drawn in
through the bottom opening and pushed out through the upper left, while
the upper right hole is used for all electrical connections.
Outlet
Sample
Intake
RAEGuard PID flow-through intake and output
The sample pump runs intermittently according to the programmable
duty cycle. The default 40% duty cycle causes the pump to be on for 8
seconds and off for 12 seconds every 20 seconds.
www.raesystems.com 5
2.2 Installation and Access Instructions
WARNING
1. A minimum of 18 inches (45 cm) of explosion-proof conduit must
be used at cable entry in group B atmospheres. CSA requires seals
in conduit exceeding 5 feet (1.5 meters) in group C atmospheres.
Note: For European applications, the installation must comply with
the requirements of EN 60079-14.
2. To prevent ignition of hazardous atmospheres, area must be free
of flammable vapors and supply circuit must be disconnected
before removing cover.
3. Keep cover tight while circuits are alive.
Mounting
First, decide where the transmitter will be mounted. (Refer to installa-
tion drawing, below.) Drill two holes in the mounting surface, with the
centers of the holes spaced 5.25 inches (133 mm) apart. Mount the RAE-
Guard PID using suitable screws.
OK FAULT LOW HIGH
+ MODE -
5.25" (133 mm)
Instrument Assembly Removal
Prior to service, make sure power is OFF. Observe all Hazardous
Location Safety procedures.
1. Unscrew the housing top from the housing
bottom.
6 RAEGuard PID
2. Insert the small cylindrical end (key) of the RAEGuard PID Magnet Key
(p/n 033-2032-000) into the hole on the left side of the support post.
SIDE VIEW
Magnet Key
End End
TOP VIEW
Two views of RAEGuard PID Magnet Key.
Support
Post
Lock Open
Magnet
Key
3. Turn the Magnet Key 90° counterclockwise to rotate the support
post to the “Open” position. You will feel the tension slacken, which
indicates you have turned the support post far enough.
Support
Post
Lock Open
Magnet
Key
Caution: Use only the provided Magnet Key to turn the support post.
Inserting a longer metal object (such as a screwdriver) may damage the
circuit board while rotating the support post.
www.raesystems.com 7
4. Carefully lift the entire instrument assembly halfway out of the
RAEGuard PID bottom housing.
Instrument assembly
halfway out of bottom
housing with 8-pin
connector plugged in
Detail of 8-pin
electrical connector
unplugged
5. Unplug the white 8-pin electrical connector. Use tweezers to discon-
nect the Tygon® tubing from the effluent (output) side of the pump.
6. Remove the entire instrument assembly from the housing bottom.
Electrical Wiring
1. Inside the housing bottom are two green terminal block plugs at-
tached to the terminal block on the circuit board. Unplug the two
terminal block plugs from the terminal block. Use tweezers, an IC
puller, or needle-nose pliers and lift the terminal blocks straight out.
8 RAEGuard PIDNote: The terminal block plugs accept 16 AWG to 28 AWG wire. Use
16 AWG or 18 AWG wire for long wiring runs, which can be up to 1
km (1,000 meters) long
2. Lace the wires through the RAEGuard PID’s wire hole(s) and con-
nect wires to the corresponding pin numbers of the terminal blocks:
Wire Pin Wire
Number Color
Alarm Common 1 Yellow
High Level Alarm Contact 2 Green
Low Level Alarm Contact 3 Orange
4-20 mA Output 6 Blue
Power Supply Negative/Output Common 7 Black
Power Supply Positive (9-36VDC) 8 Red
Not Used (troubleshooting only) 4 Brown
Not Used (troubleshooting only) 5 Purple
Instrument Assembly Installation
1. Plug both green terminal block plugs back into the correct terminal
block headers. Keep extra wires as close to the inside enclosure wall
as possible.
2. Plug the white 8-pin connector back into its socket.
3. Carefully place the instrument assembly back into the housing bot-
tom, sliding the hole in the bottom of the assembly over the support
post. As you lower the assembly into the housing, make sure the sup-
port post passes freely through the hole in the circuit board.
Note: Be sure to reconnect the effluent Tygon® tubing before placing
the assembly all the way down into the housing.
www.raesystems.com 94. Gently rock the assembly to ensure that it is properly seated and the
hole in the support post is fully visible above the circuit board.
5. Use the RAEGuard PID Magnet Key to rotate the support post 90º
clockwise, which secures the instrument assembly in the housing.
6. Tightly screw the housing top to the housing bottom.
Caution: Damage to the LCD may result if the housing is screwed
down before the assembly is seated all the way down. If you encoun-
ter resistance, remove the housing top and check that the instrument
assembly is properly seated.
7. Ground the unit using the screw connection to the lower left of the
sample inlet in order to reduce the chance of electrical shock.
Sample Gas Plumbing
Designed as a flow-through unit, the RAEGuard PID is designed to draw
a sample from up to 100 feet (30 meters), or against a vacuum of up
to 20 inches of water (38mm Hg). The pump can draw up to 40 inches
of water, but in this case, the flow will be reduced and the pump may
require more frequent maintenance. The typical flow rate without tubing
or a vacuum is 550 to 650 cc/min while the pump is on in the 20-sec-
ond cycle. See RAE Systems Technical Note 140 for details on tubing
pressure drop and time delays for extension tubing. If the gas supplied is
under pressure, throttle the flow so that it is within the range of 0.6 to 2.0
liters per minute.
Any tubing used must be inert to chemical reaction or physical adsorp-
tion. We recommend Teflon® or stainless steel tubing with an inner di-
ameter between 1/16" (1.5875 mm) and 3/16" (4.7625 mm). Do not use
Tygon® or other soft plastic tubing, as these absorb many organic vapors.
Note: Tubing of 1/16" (1.5875 mm) inside diameter may cause excessive
pressure drop and should be used only for sampling distances of ≤ 20 feet
(6 meters).
10 RAEGuard PID2.3 Display and Alarm Functions
System Initialization
When the RAEGuard PID system power is turned on, it initializes and an
“InIt” message appears on the display. As the transmitter is warming up,
the lamp and pump turn on as each component is checked, and the LEDs
blink all at once. The countdown timer appears on the screen for the 6-
second warm-up.
Reading Display
As the transmitter enters the Reading Display, it automatically starts test-
ing for errors and goes through a cycle of checking each alarm condition.
If there are no errors or alarm conditions, the green “OK” LED is lit and
the gas concentration is displayed.
If there is an error, the “Fault” LED blinks and an error message blinks
on the screen. Each alarm condition has a corresponding LED that blinks
an amber color when the readings are outside a specified range or limit.
Refer to Section 5: Troubleshooting Tips for alarm relay logic details and
Appendix B for Maximum Reading Capabilities and Indications.
Alarm Contacts
The alarm contacts can be used to drive user-supplied external alarms
such as a light or buzzer. The low alarm contact closes when the display
reads over the programmed low alarm limit. When the reading exceeds
the high alarm limit, the low alarm contact opens and the high alarm
contact closes. When the display is over-range, the high alarm contact re-
mains closed and the output jumps to 22 mA to allow remote detection. A
fault condition can be detected by a drop to 2 mA output; no dry contact
closure occurs.
Access to Programming Functions
The RAEGuard PID has no external switches, but instead uses the mag-
netic end of the RAEGuard PID Magnet Key to activate switches built
into the unit. To use the RAEGuard PID Magnet Key, briefly touch the
glass above the MODE circle or the triangles labeled [+] and [-]. Then
remove the key straight out and away from the RAEGuard PID.
Access the Calibration menu from the Reading Display by keying [MODE],
or access the Advanced menu by keying [+], [-], and then [MODE].
www.raesystems.com 112.4 Programming Menu
The programming menu lets you change the operating parameters using
the magnetic sensing key. To operate the key, briefly tap the display glass
directly above the triangles labeled [+] or [-] or the [MODE] circle.
Important! Do not drag the key sideways, or two functions may be activated.
To access the programming menu from the Reading Display, press [+],
[-], and then [MODE] in sequence. Then step through the parameters
shown below by keying [MODE]. Each tap of the key on [MODE] ad-
vances to the next item in sequence.
Note: The RAEGuard PID transmitter returns to the Reading Display
after 60 seconds of idle time.
Display Message
Submenu Parameter FGM-1000 FGM-1001 FGM-1002
Span Gas Value C100 C10.0 C10.00
Correction Factor CF1.0 CF1.0 CF1.0
Low Alarm Limit L200 L20 L5
High Alarm Limit H500 H50 H12
Pump Duty Cycle* P40 P40 P40
* If the Pump Duty Cycle value is changed, the unit should be recalibrat-
ed with zero and span calibration gases.
Note: Submenus only cycle through once. When [MODE] is keyed after
accessing the Pump Duty Cycle submenu, the transmitter returns to the
Reading Display.
Anytime a submenu screen is idle for more than 15 seconds, the transmit-
ter returns to the Reading Display.
To change a value, press [MODE] until the correct parameter appears. To
increase a value, press [+]. To decrease a value, press [-]. Press [MODE]
when you are finished changing the value.
12 RAEGuard PIDIf a value has changed, the new value blinks on the LCD. Press [-] to
discard changes and advance to the next submenu item. Press [+] to save
changes. The “SAUE” message appears on the screen to confirm changes
have been saved.
2.5 Calibration Procedures
The RAEGuard PID is calibrated using a two-point calibration process.
First, use a “zero gas.” Then use a “span gas” containing a known concen-
tration of a standard reference gas, to set the second point of reference.
Any gas can be used for calibration, but the greatest accuracy comes
from calibrating with the same gas as is being measured. However, if a
span gas cylinder of the measured gas is not available, isobutylene (IBE)
may be used to calibrate, and a Correction Factor (CF) may be applied.
See section 2.6 for Correction Factor procedures.The recommended
isobutylene span gas concentration depends on your RAEGuard PID’s
range. Below are the default values:
RAEGuard PID Range Calibration Gas
1000 ppm 100 ppm
100.0 ppm 100 ppm
20.00 ppm 10 ppm
RAEGuard PID Inlet
Connect calibration gas
cylinder and then turn on
gas.
RAEGuard PID connected to gas cylinder with calibration adapter.
www.raesystems.com 13WARNING
The calibration of all newly purchased RAE Systems instruments
should be tested with a known concentration calibration gas before the
instrument is first put into service. For maximum safety, the accuracy
of the RAEGuard PID should be checked with a known concentration
calibration gas.
Note: Zero calibration must be performed before span calibration.
To perform a calibration, you need a cylinder of zero gas, a cylinder of
span gas, and tubing. The gas regulator should provide a flow of at least
600 cc/min.
Zero Calibration
1. Connect the zero gas cylinder to the barbed gas inlet port on the
RAEGuard PID with tubing. A charcoal tube may be connected to
provide zero air.
2. To access the Calibration menu, press [MODE] from the Reading
Display. Zero calibration appears first, as indicated by the “ZErO”
message on the screen.
Optional: To advance to span calibration, press [MODE] a second
time. “SPAn” appears on the screen. Skip to the Span Calibration
instructions in the next section.
Optional: To exit the calibration menu, press [-] to return to the
Reading Display.
3. Turn on the gas flow. Press [+] to start calibration. The “Zero” LED
starts blinking, and the “ZErO” message alternates with a 60-second
countdown timer.
Optional: Before countdown reaches zero, you may press any key
to interrupt zero calibration in order to advance directly to span
calibration.
14 RAEGuard PID4. Once the countdown reaches zero, the “Zero” LED stops blinking,
and the zero calibration data is saved.
5. Turn off the gas flow from the calibration gas cylinder and remove
it. Zero calibration automatically advances to span calibration when
zero calibration is complete.
Span Calibration
1. Connect the span gas cylinder to the RAEGuard PID’s barbed gas
inlet port.
Optional: To exit the calibration menu altogether, press [-] to return
to the Reading Display. Alternatively, after 60 seconds of idle time,
it automatically returns to the Reading Display.
2. Once the countdown reaches zero, the “Span” LED stops blinking.
3. If the PID (photoionization detector) sensitivity is acceptable, the
span data is calculated and saved.
4. If the PID sensitivity is unacceptable, the screen alternately flashes a
“SPAn” and “FAIL” message until any key is pressed.
Note: If span failure occurs, it may be necessary to clean or replace
the PID lamp.
5. In case of span failure, you may restore the original calibration data
by pressing [+] when “rStr” appears on the screen. Then the transmit-
ter returns to Reading Display. Otherwise, press [-] or [MODE] to
return to zero calibration to restart the entire calibration process.
6. The calibration procedure is complete. After a few seconds, the
RAEGuard PID returns to the Reading Display.
7. Turn off the flow of gas from the calibration gas cylinder and re-
move it.
www.raesystems.com 152.6 Correction Factors for Other Gases
CAUTION: Calibrating the RAEGuard PID to a specific gas
does not make it selective to that gas. A PID is a broadband
detector that always responds to all the gases the lamp can ion-
ize, and gives the readout in equivalent units of total VOC for
the calibration gas.
Correction Factors have been determined that enable a large number of
chemicals to be quantified using only a single calibration gas, typically
isobutylene (IBE). When the instrument is calibrated with IBE, there
is no need to recalibrate it when other compounds are to be measured.
Rather, a Correction Factor (CF) can be applied to have the PID readout
in units of the new compound.
The CF is the ratio of the response to isobutylene over the response to a
particular compound. It is defined as:
CF = True VOC Concentration
PID Reading
Once the CF has been established, the true concentration can be obtained
by multiplying the reading by the CF:
True VOC Concentration = CF x PID Reading
For example, if the RAEGuard PID is calibrated to isobutylene and reads
10 ppm on a source of toluene in air (CF = 0.5), then true toluene con-
centration = 0.5 x 10 ppm = 5.0 ppm.
Correction factors are inverse to sensitivity. Compounds with CF greater
than 1.0 are less sensitive than isobutylene, and those with CF of less
than 1.0 are more sensitive than isobutylene.
Appendix A gives a short list of CFs. An extensive list is available in
RAE Systems Technical Note 106.
16 RAEGuard PIDThere are three ways to use these Correction Factors to measure the con-
centration of another gas:
A. Programming the Correction Factor
1. Calibrate the RAEGuard PID using isobutylene gas as described in
Section 2.5.
2. Program the Correction Factor for the specific gas as described in
Section 2.7.
3. The unit now directly displays the concentration in ppmv (parts per
million by volume) of the specific gas.
B. Modifying the Span Gas Value
1. When programming the span gas value, multiply the true isobutylene
concentration by the CF.
Example: Benzene has a correction factor of 0.53 relative to isobutylene gas.
Correction Factor x standard value = compensated value
Example: 0.53 x 100 ppm = 53 ppm for benzene
2. Enter a span gas value of 53 and calibrate with 100 ppm isobutylene
as described in section 2.5.
3. The unit now displays the concentration in ppmv of the specific gas
(for example, benzene).
C. Manual Conversion
1. Calibrate the RAEGuard PID unit using isobutylene gas as described
in Section 2.5.
2. Multiply the reading by the Correction Factor to obtain the true con-
centration of the specific gas.
2.7 Calibration With Other Compounds
Note: Correction Factors introduce some error, and therefore it is always
preferable to calibrate directly with the gas to be measured, if available.
However, calibrating with compounds that have Correction Factors >1 may
cause a calibration “FAIL” error. This is because compounds with low sen-
sitivity generate less of a response signal than the RAEGuard PID expects.
In this case, you should modify the span value to a number equal to:
(calibration gas concentration) / CF
Then program in the CF for measurement.
www.raesystems.com 17For example, to calibrate using a standard of 100 ppm of hexane gas,
which has a CF of 4.3, do the following:
1. Program the span gas concentration to:
100 ppm hexane = 23 ppm
4.3
2. Program the CF to 4.3.
3. Zero calibrate.
4. Apply 100 ppm hexane and initiate span calibration.
At the end of the calibration countdown, the display should indicate 23
ppm. After exiting to the normal concentration display, the reading should
be close to 100 ppm.
2.8 4-20 mA Current Output
The current output correlates with the display reading as follows:
Display Reading
Iout = 4 + (16 x Full Scale Range )
Thus, a display reading of 50 ppm on the 100 ppm model of the RAE-
Guard PID corresponds to an output of:
50
I = 4 + (16 x 100 ) = 12 mA
out
A reading of 50 ppm on the 1000 ppm model corresponds to:
50
I = 4 + (16 x 1000 ) = 4.8 mA
out
When a Correction Factor is programmed, it modifies both the display
reading and the current output. For example, if 25 ppm isobutylene is
applied to the 100 ppm model with no CF applied (that is, if CF=1.0), the
display reads 25 ppm and Iout = 8 mA. If the same gas is applied with a
CF of 2.0, the display reads 50 ppm and Iout = 12 mA.
Current outputs outside the 4-20 mA range (for example, 0 mA, 2 mA, or
22 mA) indicate failure modes (see Section 5).
18 RAEGuard PID2.9 Duty Cycle
The pump duty cycle can be varied between 30% and 70% of every 20-
second interval. Thus, a 70% duty cycle means that the pump is on for
14 seconds and off for 6 seconds. During the pump’s off time, the lamp
remains on to generate ozone and “burn off” heavy contaminants that
may build up on the lamp and sensor. The shortest duty cycle of 30%
gives the most lamp self-cleaning and thus the best sensor stability over
the long term. The longest duty cycles should be used only where rapid
response is crucial to the measurements. It is not currently possible to run
the pump continuously (that is, the duty cycle cannot be set to 100%).
3. Theory of Operation
The RAEGuard PID uses a discharge UV (ultraviolet) lamp as a high-en-
ergy photon source. After sample gas is drawn into the ionization cham-
ber by the pump, light emitted from the UV lamp ionizes a portion of the
VOC gas molecules. A pair of electrodes inside the ionization chamber
captures the ions and measures the resulting current. Because the mea-
surement is essentially non-destructive, the effluent gas can be used for
further analysis if desired.
The RAEGuard PID is a microcontroller-based instrument. After the
electrical signal from the PID sensor is conditioned and digitized, the mi-
crocontroller processes the data and then displays the results locally and
reconstructs the digital data into a standard 4-20 mA current signal.
The lamp failure detector monitors the UV light source, and the pump
current sensor monitors the pump operation. Failure conditions are im-
mediately indicated by LED, a message on the display, and a specified
electrical current signal.
The instrument has three magnetic sensing keys. Using the RAEGuard
PID Magnet Key, it is possible to calibrate the RAEGuard PID and
change the alarm level setting via the magnetic front-panel keypad.
The instrument is powered by a DC power supply located in a safe area.
The power supply on the printed circuit board contains a switching and
www.raesystems.com 19linear regulator that converts the main input voltage to 3.3V and 5V DC
to power the entire circuit.
Gas Sensor Electrometer A/D Transmitter 4-20 mA
In
Pump UV
Lamp Display
Gas
Out Power
Lamp Driver Microcontroller
Supply
Keypad
Flame-arresting From
metal frit Controller
4. Maintenance
You should clean the PID sensor and the lamp when one of the following
occurs:
1. The reading is inaccurate even after calibration.
2. The reading is very sensitive to air moisture.
3. A chemical liquid has been sucked into the unit and has damaged it.
Housing
Display
Lock hole
Support post
Pump PID sensor
Terminal block
Sensor gasket
#005 O-ring
Gas inlet
Housing base
Exploded view of RAEGuard PID components.
20 RAEGuard PID4.1 Cleaning the PID Sensor and Lamp
During the course of normal operation, a film of gas vapor may build up
inside the PID sensor. The rate of film build-up depends on the type and/
or the concentration of vapors being sampled. Cleaning the sensor helps
avoid a drifting response at high humidity. In clean ambient environ-
ments, clean the sensor once a year. Refer to Section 5 Troubleshooting
Tips for indications that the sensor needs cleaning.
If the lamp does not turn on or there is excessive
film build-up on the lamp window, the RAEGuard
PID produces a failure signal (2 mA) for current
output. This indicates the lamp requires cleaning.
Periodically clean the lamp window to remove film
deposits and restore lamp sensitivity. Exercise care
when cleaning the lamp window so that the surface
PID Sensor is not damaged.
Follow this procedure for cleaning lamps or sensors:
1. Remove the instrument assembly from the hous-
ing body. (Refer to Section 2.2, Installation Instruc-
tions.) The instrument assembly may also be sent in
for repair. Refer to Chapter 5 Troubleshooting Tips.
Lamp
2. Loosen the two screws below the sensor, but do
not completely remove it.
3. Use the IC puller to remove the sensor. Pull it straight out with a
slight rocking motion, using some force, since the sensor will be
snug in its place. Do not touch the sensor’s electrode pins.
4. Dip the entire PID sensor into GC Grade methanol. Cleaning the
PID sensor in an ultrasound bath for about 15 minutes is highly rec-
ommended. Do not disassemble the sensor for cleaning.
Note: Never touch the window surface with fingers or anything that
might leave behind film or dirt..
5. Dry the sensor thoroughly. Never touch the electrode pins of the sen-
sor with your hands.
6. Examine the sensor for visible damage such as corrosion, bent pins,
or any other mechanical damage. If the sensor is corroded or dam-
aged, contact RAE Systems service for replacement.
7. Carefully examine the sensor O-ring for cracks that may cause a
leak. Replace as necessary.
www.raesystems.com 218. Carefully pull out the lamp. Avoid contact with the flat window surface. 9. Clean the lamp window surface by wiping it with anhydrous methanol* on a cotton swab. Rub in a circular motion with moderate pressure. * Caution: Water degrades window surfaces. 10. After cleaning, hold the lamp up to the light at an angle to detect any remaining film. Repeat the process until the lamp window is clean. 12. Re-insert the clean lamp, making sure the lamp’s 1/2" Teflon® O- ring is in place. 13. Re-insert the clean sensor block. One of the four pins is thicker than the other three to act as a key and ensure proper alignment. 14. Replace the instrument assembly into the housing body (refer to Section 2.2 Installation Instructions). 15. Inspect the large O-ring on the body for damage and replace it if necessary. Then screw on the cover. 4.2 Pump Replacement Follow this procedure for removing the pump: 1. Remove the instrument assembly from the housing body. (Refer to Section 2.2, Installation Instructions.) The instrument assembly may also be sent in for repair. Refer to Chapter 5 Troubleshooting Tips. 2. Disconnect the white 5-conductor con- nector that connects the pump and the circuit board. 22 RAEGuard PID
3. Disconnect the tube from the left inlet on
the pump. A small-blade screwdriver may
be helpful in prying the hose off of the
connector. Alternatively, you may use an
IC puller or needlenose pliers.
4. Hold the pump and remove the two Phillips screws from the base of
the instrument assembly.
5. Lift the pump out of the instrument assembly.
Replace the pump with a new pump (part number 033-3003-100). Follow
this procedure:
1. Slide the pump into place inside the instrument assembly and locate
its two screw holes over the matching holes in the instrument assem-
bly’s base.
2. Screw in the two Phillips screws until the pump is held snugly.
3. Reconnect the hose to the left pump inlet.
Important: Make sure to reconnect the tube between the effluent
(output) port and the right port on the pump.
4. Connect the 5-pin connector of the cable from the pump to the
matching connector base on the circuit board.
5. Replace the instrument assembly into the housing body (refer to
Section 2.2 Installation Instructions).
6. Inspect the large O-ring on the body for damage and replace it if
necessary. Then screw on the cover.
4.3 Filter Adapter
The RAEGuard PID must not be operated without a filter in the inlet
path. Refer to RAE Systems Technical Note TN-187 for further details.
www.raesystems.com 235. Troubleshooting Tips
Note: Before diagnosing measurement problems, perform zero and span
calibration.
Symptom Reading abnormally high.
Reason Dirty sensor block. Excessive moisture.
Solution Clean or replace sensor block. Eliminate/control
source of moisture and/or temperature difference.
Symptom “Span Failure” signal.
Reason Dirty sensor. Weak/defective lamp.
Solution Clean sensor block. Replace sensor block. Re-
place lamp.
Symptom Reading abnormally low; reading jumping
around randomly.
Reason Dirty or weak lamp. Incorrect calibration. Sample
tubing restricts flow or absorbs gas.
Solution Clean or replace lamp. Recalibrate unit. Use inert
or wider-bore tubing.
Symptom No response during calibration.
Reason No standard gas flow. Pump defective or blocked.
Low sensitivity to calibration gas. Weak lamp.
Solution Make sure standard gas flows into unit. Unblock
flow path or replace pump. Use different calibra-
tion gas. Replace lamp.
Symptom Full-scale measurement in humid environment.
Reason Dirty or wet sensor.
Solution Clean sensor with methanol using an ultrasound
bath, and then dry thoroughly.
Symptom Low 4-20 mA output.
Reason Power supply is lower than specified.
Solution Check power supply voltage and connection.
24 RAEGuard PIDInstrument Failure Table
Error & Reason E001 Lamp failure.
Solution Change the lamp.
Error & Reason E002 Pump failure.
Solution Make sure wires are not loose and that there
are no mechanical obstructions in the pump
motor. Replace pump assembly.
Error & Reason E003 Calibration fails.
Solution Perform zero and span calibrations. Clean
sensor. Clean or change lamp. Check gas flow
path. Check calibration gas.
Error & Reason E004 Zero drift.
Solution Perform zero and span calibration. Electri-
cally ground to housing using screw at lower
left of inlet.
Error & Reason E005 Gas sensitivity beyond range of instru-
ment.
Solution Use different calibration gas and use within
measurement range limits. Dilute gas.
www.raesystems.com 25Alarm Relay Logic
External LED LCD Analog
Alarm Output
Exceed Low Low Alarm Low Reading Based on
Alarm Limit reading
Exceed High High Alarm High Reading Based on
Alarm Limit reading
Over range High Alarm High Flashing 22 mA
8888
ADC Saturated High Alarm Fault Flashing 2 mA
(max) E005
Sensor Fault, Low Alarm Fault Flashing 2 mA
Lamp Fail E001
Sensor Fault, Low Alarm Fault Flashing 2 mA
Pump Fail E002
Sensor Fault, Low Alarm Fault Flashing 2 mA
Calibration Fault E003
Sensor Fault, Low Alarm Fault Flashing 2 mA
Sensor Drift E004
Appendix A. Correction Factors
The following is a partial list of Correction Factors for a number of com-
monly used compounds for the PID sensor with 10.6 eV lamp. (Refer
to RAE Systems Technical note TN-106 at www.raesystems.com for
complete lists of Correction Factors).
Table A: Correction Factors for PID with 10.6 eV Lamp
Compound Correction Factor
Acetylaldehyde 5.5
Acetic acid 14
Acetone 1.1
Acrylic acid 12
Allyl alcohol 2.4
Ammonia 9.7
26 RAEGuard PIDTable A: Correction Factors for PID with 10.6 eV Lamp
Continued
Benzene 0.53
Butadiene 1.0
Butyl acetate, n- 2.6
Butyl acrylate, n- 1.6
Carbon disulfide 1.2
Cyclohexane 1.4
Cyclohexanone 1.0
Dichloroethene, t-1,2- 0.45
Diesel Fuel 0.66
Diethylamine 0.97
Dimethylhydrazine, 1,1- 0.78
Epichlorohydrin 10
Ethanol 12
Ethene 10
Ethyl acetate 4.6
Ethyl acrylate 2.4
Ethyl benzene 0.52
Ethyl ether 1.1
Ethyl hexyl acrylate, 2- 1.1
Ethyl sulfide 0.51
Gasoline vapors 0.85
Gasoline, whole 1.0
Heptane, n- 2.6
Hexamethyldisilazane 0.24
Hexane, n- 4.3
Hydrazine 2.6
Hydrogen sulfide 4.1
Isobutane 120
Isobutene 1.00
Isobutyl acrylate 1.5
Table continued on next page
www.raesystems.com 27Table A: Correction Factors for PID with 10.6 eV Lamp Continued Isopropanol 6.0 Jet fuel JP-4 0.99 Jet fuel JP-5 0.6 Jet fuel JP-8 0.6 Methyl acrylate 3.7 Methyl ethyl ketone 0.86 Methyl isobutyl ketone 1.2 Methyl methacrylate 1.4 Methyl t-butyl ether 0.91 Nitric oxide 5.2 Octane, n- 1.8 Perchoroethene 0.58 Pinene, a- 0.31 Pinene, b- 0.37 Propene 1.7 Styrene 0.42 Tetrahydrofuran 1.8 Toluene 0.5 Trichloroethene 0.52 Vinyl chloride 2.0 Xylene, m- 0.43 Xylene, o- 0.59 Xylene, p- 0.45 For more data, see RAE Systems Technical Note TN-106. The VOC Correction Factors are measured relative to isobutylene gas at
Appendix B. Maximum Reading Capabilities and Indications
Model Range Saturation Analog Saturation Analog Over
Value Output Value Output for Range
Over Range Display
FGM-1002 0.0 ppm - 20.0 ppm 20.62 ppm 4 mA - 20.0 mA 20.5 mA 22 mA Flashing
8888
FGM-1001 0.1 ppm - 100 ppm 103.1 ppm 4 mA - 20.0 mA 20.5 mA 22 mA Flashing
8888
FGM-1000 0.0 ppm - 1000 ppm 1031 ppm 4 mA - 20.0 mA 20.5 mA 22 mA Flashing
8888
www.raesystems.com
29Appendix C. Limited Product Warranty RAE Systems (RAE) warrants the RAE products to the original owner purchased directly from RAE or an authorized RAE Reseller to be free of defects in workmanship for a period of one year from the date of origi- nal shipment to owner exclusive of consumables, including batteries, filters, and calibration gases. Pumps and 10.6 eV electrodeless discharge lamps are warranted for one year. RAE’s obligation under this warranty is limited to replacing or repairing, at RAE’s option, any defective part if returned to a RAE authorized factory repair center, with shipping charges prepaid by the buyer, and which, upon inspection by RAE, shall prove to have been defective in normal use and service. To maintain warranty, Purchaser must perform maintenance and calibra- tion as prescribed in the Operation and Maintenance manual. In the event of defect, Purchaser will notify RAE designated factory repair center in advance, and if trouble diagnosis procedures are unable to determine and remedy the condition, a Return Material Authorization (RMA) will be issued to assure proper repair and logistics tracking. Warranty does not extend to any equipment malfunction or damage which results from alteration, accident, theft, misuse, abuse, abnormal use, improper or unauthorized repairs, or improper maintenance. RAE neither assumes nor authorizes any other firm or person to assume on RAE’s behalf any liability in any way connected with the sale of RAE products. This express warranty shall extend to the buyer of record only and not to sales made by the buyer’s customers. Except for the warranty of title, the foregoing express warranty is in lieu of any and all other warranties, whether expressed or implied, including the implied warranties of fitness for a particular purpose and merchantability. Seller’s liability under the warranty provided herein exclusive of insurance process shall be limited to a refund of purchase price. 30 RAEGuard PID
Appendix D. RAE Systems Contacts
RAE Systems by Honeywell World Headquarters
3775 N. First St.
San Jose, CA 95134-1708 USA
Phone: 408.952.8200
Fax: 408.952.8480
E-mail: customerserv@raesystems.com
Web Site: www.raesystems.com
RAE Systems Technical Support
Monday through Friday, 7:00AM to 5:00PM Pacific Time
+1.888.723.4800 (toll-free)
email: tech@raesystems.com
RAE Systems Europe ApS
Kristinehøj 23 A
DK-2770 Kastrup
Denmark
Phone: +45 86 52 51 55, From 8.00 - 17.00
Fax: +45 86 52 51 77
RAE Systems (Hong Kong) Ltd.
Room 8, 6/F, Hong Leong Plaza
33 Lok Yip Road
Fanling, N.T. HONG KONG
Phone: +852.2669.0828
Fax: +852.2669.0803
www.raesystems.com 31RAE Systems by Honeywell
World Headquarters
3775 N. First St.
San Jose, CA 95134-1708 USA
Phone: 408-952-8200
Fax: 408-952-8480
E-mail: customerserv@raesystems.com
p/n 033-4001-001 Rev B, January 2009
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