Rae RAEGuard EC, RAEGuard LEL, RAEGuard IR User Manual

RAEGuardS EC

Toxic Gas and Oxygen Transmitter

RAEGuardS LEL

Combustible Gas Transmitter

RAEGuardS IR

Non-Dispersive Infrared (NDIR)

Transmitter

User’s Guide

P/N 033-4117-E00 Rev A August 2009

RAEGuardS EC / LEL / IR User’s Guide

- 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. The user should understand how
to set the correct parameters and interpret the obtained results.

CAUTION!

To reduce the risk of electric shock, turn the power off before
removing the instrument cover. Disconnect the power before
removing the sensor module for service. Never operate the
instrument when the cover is removed. Remove instrument
cover and sensor module only in an area known to be non­hazardous.

WARNING!

The calibration of all newly purchased RAE Systems
instruments should be tested by exposing the sensors to known
concentration calibration gas before the instrument is used or
put into service. For maximum safety, the accuracy of the
RAEGuard

S

should be checked by exposing the sensor(s) to

known concentration calibration gas every three (3) months.

1

RAEGuardS EC / LEL / IR User’s Guide

Contents

1. General Information......................................................................... 3

1.1 General Specifications............................................................... 6

RAEGuard

S

EC Specifications ................................................. 6

RAEGuard

S

IR Specifications................................................... 7

RAEGuard

S

LEL Specifications................................................ 9

2. Operation....................................................................................... 10

2.1 Physical Description ................................................................ 11

2.2 Installation and Access Instructions ........................................ 11

Mounting.................................................................................. 12

Instrument Assembly Removal................................................ 13

Electrical Wiring....................................................................... 14

Instrument Assembly Installation............................................. 15

Earth Grounding Instructions................................................... 16

2.3 Display And User Interface...................................................... 18

User Interface .......................................................................... 18

Magnet Key ............................................................................. 18

Using The Magnet Key ............................................................ 19

System Initialization................................................................. 19

Reading Display ...................................................................... 20

Alarm Contacts ........................................................................ 20

2.4 Calibration ............................................................................... 21

Zero Calibration ....................................................................... 22

Span Calibration ...................................................................... 23

2.5 Advanced Menu (EC & LEL) ................................................... 25

2.6 Advanced Menu (IR)................................................................ 31

2.7 Restoring Default Values (EC & LEL) ................................... 31

3. Theory of Operation....................................................................... 33

4. Maintenance .................................................................................. 35

5. Troubleshooting............................................................................. 35

Table A: EC Sensor configuration ................................................ 37

6. ModBus/RS-485 Information ......................................................... 38

2

RAEGuardS EC / LEL / IR User’s Guide

1. General Information

RAEGuard

S

EC The RAEGuard

S

EC is a fixed electrochemical

detector for oxygen and toxic gas (CO, H

2

S, SO2, NO, NO2, Cl2, O2,

ClO

2

, NH3, PH3, HCN and ETO). It operates with voltages from 9 to
36 VDC and provides an analog (4 to 20mA) output signal and digital
(RS-485, ModBus) output signal within the corresponding ranges of
gas detection. The RAEGuard

S

EC uses an interchangeable
electrochemical smart sensor, which can be pre-calibrated
independently offline. Housed in an explosion-proof enclosure, the
RAEGuard

S

EC is equipped with a local digital display of the gas

concentration and unit of measurement, status LEDs, and function

keys for performing calibration.

RAEGuard

S

IR The RAEGuard

S

IR is fixed non-dispersive infrared
(NDIR) detector for hydrocarbon combustible gases, carbon dioxide,
and other gases, It operates with voltages from 9 to 36 VDC and
provides an analog (4 to 20mA) output signal and digital (RS-485,
ModBus) output signal within the corresponding ranges of gas
detection of 0 to 100% LEL or 0 to 50,000 ppm CO

2

. The RAEGuardS
IR uses a smart NDIR sensor, which can be pre-calibrated
independently offline. Housed in an explosion-proof stainless steel
enclosure, the RAEGuard

S

IR is equipped with a local digital display

of the gas concentration, status LEDs, and function keys for

performing calibration.

RAEGuard

S

LEL The RAEGuard

S

LEL is a fixed, highly poison­resistant catalytic bead lower explosion limit (LEL) sensor for
combustible gases detection. It operates with voltages from 9 to 36
VDC and provides an analog (4 to 20mA) output signal and digital
(RS-485, ModBus) output signal within the corresponding range of 0
to 100% LEL. The RAEGuard

S

LEL uses a smart LEL sensor, which
can be pre-calibrated independently offline. Housed in an explosion­proof stainless-steel enclosure, the RAEGuard

S

LEL is equipped with

a local digital display of the gas concentration, status LEDs, and

function keys for performing calibration.

3

RAEGuardS EC / LEL / IR User’s Guide

Key features:

• Interchangeable smart electrochemical sensor that can be

calibrated offline

• 4 to 20mA analog output signal.

• RS-485 digital communication in ModBus Protocol

• Explosion-proof stainless-steel enclosure for hazardous

environment applications

• Magnetic-key interface eliminates the need to open the explosion-

proof housing when adjusting parameters.

• LCD and status/error LEDs

• LED alarms when High or Low alarm point is reached

• Operation at 9 to 36 VDC

• Two dry contacts (<30V, 2A) normally open (or normally closed),

one for High and Low alarm, another for Fault alarm

Applications:

• Waste water treatment plants

• Petroleum and natural gas fields

• Marine and offshore oil wells

• Refineries and petrochemical plants

• Solvent recovery systems

• Chemical plants

• Industrial safety

• Sewers and pipelines

• Pulp & paper plants

• Heavy industry

• Power plants

• Steel mills

4

RAEGuardS EC / LEL / IR User’s Guide

Hazardous Location Classification:

ATEX: II 2G Ex d IIC T6 -40° C < T

amb

< +60° C

Complies with EN60079-0 :2004, EN60079-1 :2004

Example Of Name Plate On RAEGuardS Models:

Notes:

Sensor Name is replaced by the actual sensor name.
FGM-1XXXS is replaced by model number.
* <

4

** Optional

5

RAEGuardS EC / LEL / IR User’s Guide

1.1 General Specifications

RAEGuardS EC Specifications

Size

7.4" L x 5.9" W x 4.3" H

188mm x 150mm x 109mm

Weight

7.7 lbs

3.5 kg

Detector

Off-line pre-calibrated interchangeable smart

electrochemical sensor

Calibration

2-point calibration

Certification

ATEX: II 2G Ex d IIC T6 -40° C <

T

amb

< +60° C
Complies with EN60079-0 :2004, EN60079­1 :2004

IP Rating

IP-65

Power

9 to 36VDC, max 40mA at 24V or 1W

Output

4-20mA
RS-485, baud-rate 4.8, 9.6 or 19.2kb/sec

Sampling

Internal diffusion

Display

7-segment, 4-digit LCD and 4 color-coded
alarm LEDs

User Interface

Magnetically accessed keys for non-intrusive
calibration and adjustment

Temperature

-40°

C to 60° C

Humidity

0% to 95% relatively humidity (non-condensing)

Pressure

0.9 to 1.1 Atm

Dry contact

Max 30V, 2A

Dry Contacts

30V, 2A, normally open (or normally closed),
one for High and Low alarm, another for Fault

alarm

Terminal

AWG 24-12

Mounting

2 holes, 5.25" (133mm) from center to center

6

RAEGuardS EC / LEL / IR User’s Guide

RAEGuardS IR Specifications

Size

6.6” L x 5.9” W x 4.3” H

168mm x 150mm x 109mm

Weight

7.7 lbs or 3.5 kg

Detector

Protected, Off-line pre-calibrated,

interchangeable smart NDIR sensor

Calibration

2 point calibration

Range

CO

2

：

0 to 50000 ppm

CH

4

：

0 to 100% LEL

Resolution

CO

2

：

When CO

2

< 10000 ppm，resolution is 1 ppm；

When CO

2

>10000 ppm，resolution is 1000 ppm

CH

4

：

resolution is 1% LEL.

Response Time

(T

90

)

T

90

≤30 seconds

Certification

ATEX: II 2G Ex d IIC T6 -40° C <

T

amb

< +60° C

Complies with EN60079-0 :2004, EN60079-1 :2004

IP Rating

IP-65

Power

9 to 36VDC, max 60mA at 24V or 1.5W

Output

4-20mA
RS-485
Baud rate: 4.8, 9.6 or 19.2kb/sec

Sampling

Internal diffusion

Display

7-segment, 4-digit LCD
4 color-coded LEDs

User Interface

Magnetically accessed keys for non-intrusive
calibration and adjustment

Operating

Temperature

CO

2

: -20° C to +60° C

CH

4

: -40° C to +60° C

Humidity

0 to 95% relative humidity (non-condensing)

Pressure

0.9 to 1.1 Atm

Dry Contacts

30V, 2A, normally open (or normally closed), one

for High and Low alarm, another for Fault alarm

Terminal

AWG 24 to 12 (diameter 0.5mm to 2mm)

Mounting

2 holes 5.25" (133mm), from center to center

7

RAEGuardS EC / LEL / IR User’s Guide

RAEGuardS IR Default Sensor Settings

Gas Range Resolution Span Gas

Carbon Dioxide (CO2)

0

to 50,000

ppm

10 ppm or

1000 ppm

2000 ppm to

10000 ppm

Methane (CH4)

0

to 100%

LEL

1% LEL

20% LEL to

99% LEL

Note: When CO

2

< 10000 ppm, the LCD displays the reading. When

CO

2

>10000, the LCD displays X.XE4 (which represents X.X x 10

4

).

For example, when the monitor display 1.5E4, it means 15000 ppm;
when the LCD displays 3.6E4, it means 36000 ppm. The LCD on the

RAEGuard

S

IR CH4 displays the %LEL (percentage of LEL) reading.

For example, when the LCD displays 25, it means 25% LEL; when
the LCD displays 75, it means 75% LEL.

8

RAEGuardS EC / LEL / IR User’s Guide

RAEGuard

S

LEL Specifications

Size

6.6” L x 5.9” W x 4.3” H

168mm x 150mm x 109mm

Weight

7.7 lbs or 3.5 kg

Detector

Protected, Off-line pre-calibrated,
interchangeable catalytic bead smart LEL

sensor

Calibration

2 point calibration

Range

0 to 100% LEL

Resolution

1% LEL

Response Time

(T

90

)

<

15 seconds to 90% of reading to 50% LEL

methane

Certification

ATEX: II 2G Ex d IIC T6 -40° C <

T

amb

< +60° C
Complies with EN60079-0 :2004, EN60079­1 :2004

IP Rating

IP-65

Power

9 to 36VDC, max 60mA at 24V or 1.5W

Output

4-20mA
RS-485, Baud-rate 4.8, 9.6 or 19.2kb/sec

Sampling

Internal diffusion

Display

7-segment, 4-digit LCD
4 color-coded LEDs

User Interface

Magnetically accessed keys for non­intrusive calibration and adjustment

Operating

Temperature

-40° C to +60° C

Humidity

0 to 95% relative humidity (non-condensing)

Pressure

0.9 to 1.1 Atm

Dry Contacts

30V, 2A, normally open (or normally closed),
one for High and Low alarm, another for

Fault alarm

Terminal

AWG 24 to AWG 12 (diameter 0.5mm to
2mm)

Mounting

2 holes, 5.25" (133mm) from center to
center

9

RAEGuardS EC / LEL / IR User’s Guide

2. Operation

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 used or put into service. For
maximum safety, the accuracy of the RAEGuard

S

EC should be
checked by exposing the sensor(s) to a known concentration
calibration gas, after a period of time.

Calibration should be verified daily during the period of initial use in
the intended atmosphere to ensure nothing is poisoning the
sensor(s). The period of initial use must be of sufficient duration to
ensure that the sensors are exposed to all conditions that might have
an adverse effect on the sensors.

Verify the calibration with a known concentration test gas before use.
This “bump” test is very simple. Recalibrate the unit if readings are
off.

Prior to factory shipment, the RAEGuard

S

EC is calibrated and tested
using span gas. However, the user should calibrate the instrument
before the first use. After the unit is installed, run for 24 hours, and
calibrated, it is ready for immediate operation. Calibration setting
values for EC sensors are shown as Table A (on page 32).

Kit Accessories include: Calibration Adapter, RAEGuard Magnet

Key, and User’s Guide.

10

RAEGuardS EC / LEL / IR User’s Guide

11

2.1 Physical Description

The design of RAEGuardS allows it to be easily mounted and
interfaced to a fixed-point gas monitoring system. The RAEGuardS
EC and LEL are housed in a 7.4" L x 5.9" W x 4.3" H (188mm x
150mm x 109mm) case with two holes 5.25" (133 mm) from center to
center. The RAEGuard

S

IR’s dimensions vary slightly because of the

sensor size: 6.6" L x 5.9" W x 4.3" H (168mm x 150mm x 109mm).

5.0" (127)

5.24" (133)

Ø3.15"(8)

3/4" -14NPT

7.40" (188)

4.92" (125)

Note: This dimension

is 6.6

" (168mm) on the

RAEGuardS IR and
LEL.

Ø 4 1/2" (114.30)

3/4" -14NPT

1.04" (26.4)

4.29" (109.0)

RAEGuardS EC / LEL / IR User’s Guide

2.2 Installation and Access Instructions

WARNING

1. A minimum of 18" (457mm) of explosion-proof conduit
must be used at cable entry in group A and B
atmospheres. CSA requires seals in conduit exceeding 5'
(1.524 m) in group C atmospheres.

2. To prevent ignition of hazardous atmospheres, area must
be free of flammable vapors and supply circuit must be
disconnected before removing cover.

3. For European application, the installation must comply
with the requirements of EN 60079-14.

Mounting

First, decide where the transmitter will be mounted. (Refer to

installation drawing, below.) Drill two holes in mounting surface, with

the center of the holes 5.25" (133mm) apart.

12

RAEGuardS EC / LEL / IR User’s Guide

Instrument Assembly Removal (EC and LEL)

Prior to service: Make sure power is OFF. Observe all
Hazardous Location Safety procedures.

1. Unscrew the housing lid
from the housing body by
rotating it counter­clockwise.

A

s shipped, one
of the conduit holes is
covered by the provided
hex-head plug. The other
conduit is shipped with
connected wires.

2. Pull off the retaining clip
to release the

instrument assembly.

3. Tilt the instrument assembly

90˚.

4. Unlock the black 16-pin
connector.

5. Lift the entire instrument
assembly out of the housing.

6. Unlock the white 8-pin
connector.

7. Remove the sensor.

Picture shows
disassembled instrument

13

RAEGuardS EC / LEL / IR User’s Guide

Instrument Assembly Removal (IR)

Prior to service: Make sure power is OFF. Observe all
Hazardous Location Safety procedures.

1. Unscrew the housing lid
from the housing body by
rotating it counter­clockwise.

A

s shipped, one
of the conduit holes is
covered by the provided
hex-head plug. The other
conduit is shipped with
connected wires.

6. Unlock the 12-pin
connector.

2. Pull off the retaining clip

to release the

instrument assembly.

7. Remove the sensor.

Picture shows
disassembled instrument

6. Tilt the instrument assembly

90˚.

7. Unlock the 20-pin connector.

8. Lift the entire instrument
assembly out of the housing.

14

RAEGuardS EC / LEL / IR User’s Guide

Electrical Wiring

1. Inside the housing bottom, unplug the two green terminal block

plugs from the terminal block on the PC boards. Note: The

terminal block plugs accept 12 AWG to 24 AWG wire.

2. Lace the wires through the RAEGuardS EC’s wire hole(s) and

connect wires to the corresponding pin numbers of the terminal
blocks:

Terminal Wire Pin#

Alarm Common (COM) 1
High/Low Alarm (ALM1) 2

Fault Alarm (ALM2) 3
RS485A (485A) 4

Block 1

RS485B (485B) 5
4-20 mA Output (4-20mA) 6

Power Supply - Output Common (P-) 7

Block 2

Power Supply + (9 to 36VDC) (P+) 8

Instrument Assembly Installation

1. Plug all terminal block plugs into the correct terminal block headers.

Keep the extra wires as close to the inside enclosure wall as possible.

2. Screw the sensor module to the housing and plug the 8-pin (EC) or 10-

pin (LEL model) or 12-pin (IR model) connector back into its socket.

3. Plug the 16-pin (EC or LEL model) or 20-pin (IR model) connector back

into its socket.

4. Pull off the clip to place the instrument assembly back into the housing

bottom.

5. Tightly screw the housing top to the housing bottom.

15

RAEGuardS EC / LEL / IR User’s Guide

Earth Grounding Instructions

External Earth Grounding

Fasten the crimped ground wire with hardware as illustrated below.
The wire should have a minimum cross-section area of 4mm

2

for its

conductor.

Wire
(Min. 4 mm

2

cross-section)

Crimped terminal

M4 flat washer

M4 Split washer

M4 Screw

Internal Earth Grounding

Use the same hardware as shown in the illustration of external earth
grounding. The wire should be no less than the size of the power
lines.

Internal earth
grounding

16

RAEGuardS EC / LEL / IR User’s Guide

Finished Grounding Wires

Internal and external grounding are shown here, as well as an
alternate external grounding point. Always follow local electrical
guidelines.

External earth
grounding

Internal earth
grounding

Alternate
grounding
point

17

RAEGuardS EC / LEL / IR User’s Guide

2.3 Display And User Interface

User Interface

The RAEGuardS EC’s user interface consists of four status LEDs, a 4­digit LCD display, and three keys, [+], [MODE], and [-]. The three
keys are operated by using the Magnet Key.

RAEGuardS EC user interface.

Magnet Key

The RAEGuardS EC has no external switches, but instead uses the
magnetic end of the RAEGuard Magnet Key (p/n 033-2032-000) to
activate switches built into the unit.

Magnet

SIDE VIEW

TOP VIEW

RAEGuard Magnet Key.

18

RAEGuardS EC / LEL / IR User’s Guide

Using The Magnet Key

Using the magnet end of the 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

S

EC.

RAEGuard Magnet Key touching glass above the [+] triangle.

Important! Never drag the key sideways, or two functions may be

activated.

System Initialization

When the RAEGuardS EC system power is turned on, it initializes and
an “InIt” message appears on the display. As the transmitter is
warming up, each component is checked, and the LEDs blink all at
once. The countdown timer appears on the screen for the warm-up.

19

RAEGuardS EC / LEL / IR User’s Guide

Reading Display

As the transmitter enters the Reading Display, it automatically starts
testing 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. Each alarm condition has a corresponding LED that blinks an
amber color when the readings are outside a specified range or limit.

Alarm Contacts

The alarm contacts or alarm relay can be used to drive user-supplied
external alarms such as a light or buzzer. The external alarms open in
normal conditions and close when an alarm occurs.

Default Alarm Relay Logic

External

Alarm

LED LCD Analog Output

Exceeds Low alarm
limit

ALM 1 Alarm Low reading Based on

reading

Exceeds High alarm
limit

ALM 1 Alarm High reading Based on

reading

Over Range ALM 2 Alarm High 8888 22mA

Calibration fail ALM 2 Alarm Fault Flashing

E003

2mA

Sensor drift* ALM 2 Alarm Fault Flashing

E004

2mA

ADC saturated
*(max)

ALM 2 Alarm Fault Flashing

E005

2mA

* RAEGuardS EC and LEL only.

20

RAEGuardS EC / LEL / IR User’s Guide

2.4 Calibration

WARNING

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 used or
put into service. For maximum safety, the accuracy of the
RAEGuard

S

should be checked by exposing the sensor to a

known concentration calibration gas, after a period of time.

T

he RAEGuard

S

is calibrated using a two-point calibration process. First, use
a “zero gas.” Then use a “span gas” containing a known concentration of a
standard reference gas, to set the second point of reference.

Note:

The zero

calibration must be performed before the span calibration.

RAEGuard

S

connected to gas cylinder with a calibration adapter.

Gas calibration requires a bottle of zero gas, a bottle of span gas, and
a calibration adapter.

21

RAEGuardS EC / LEL / IR User’s Guide

Zero Calibration

1. Connect the zero gas cylinder to the metal filter gas adapter on

the RAEGuard

S

transmitter using the provided calibration

adapter.

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 Span
Calibration instructions on the next page.

Optional: To exit the Calibration menu, press [-] to return to the

Reading Display.

3. Turn on the gas flow. Allow gas to flow into the sensor for 30

seconds before zero calibration. Then press [+] to start
calibration. The “Zero” LED starts blinking, and the “Zero”
message alternates with a countdown timer.

Optional: Before the countdown reaches zero, you may press

any key to interrupt zero calibration and advance to span
calibration.

4. Once the countdown reaches zero, the “Zero” LED stops

blinking, and the zero calibration data is saved.

Note: The transmitter returns to the Reading Display after 60
seconds of idle time.

5. Turn off the zero calibration gas and remove the cylinder.

22

RAEGuardS EC / LEL / IR User’s Guide

Zero calibration automatically advances to span calibration when
complete.

Span Calibration

1. Connect the span gas cylinder to the metal filter gas adapter on

the RAEGuard

S

transmitter using the provided calibration

adapter.

23

RAEGuardS EC / LEL / IR User’s Guide

Optional: To access span calibration from the Reading Display,

press [MODE]. After “Zero” appears on the screen, press

[MODE] a second time to advance to span calibration.

Optional: To access span calibration after zero calibration has

already started, press any key to advance to span calibration.

Optional: To exit the calibration menu, press [-] to return to the

Reading Display.

Note: It is not necessary to exit manually. After 60 seconds of idle time,

the RAEGuard

S

automatically returns to the Reading Display.

2. Turn on the gas flow. First, let gas flow into the sensor for 30

seconds before span calibration.Then press [+] to start

calibration. The “Span” LED starts blinking. The “Span” message
alternates with a countdown timer.

Note: Wait for the entire countdown for a complete calibration.

Optional: Before the countdown reaches zero, you may press

any key to interrupt span calibration and return to the Reading
Display.

3. Once the countdown reaches zero, the “Span” LED stops

blinking.

4. If the sensor sensitivity is unacceptable, the screen alternately

flashes a “Span” and “FAIL” message until any key is pressed.

Note: If span calibration fails, it may be necessary to replace the

sensor.

5. You may choose to press [-] or [MODE] to return to zero

calibration and restart the entire calibration process, or press [+]
to go to the Reading Display.

24

RAEGuardS EC / LEL / IR User’s Guide

6. If the sensor’s sensitivity is acceptable, the span data is

calculated and saved.

7. The calibration procedure is complete. After a few seconds, the

transmitter returns to the Reading Display.

8. Turn off span calibration gas and remove the cylinder.

2.5 Advanced Menu (EC & LEL)

The Advanced menu on the RAEGuardS EC and LEL allows you to
change the values for each reading and setup option. To access the

Advanced menu from the Reading Display, first press [+], [-],and then

[MODE] in sequence. Then scroll through the parameters shown
below by pressing [MODE].

Once you have entered the Advanced Menu, you can edit the
parameters for each item in the list.

25

RAEGuardS EC / LEL / IR User’s Guide

Note: Anytime a submenu screen is idle for more than 60 seconds,

the transmitter returns to the Reading Display.

Advanced Menu

Display Explanation

CALu Calibration Concentration Value
CF Correction Factor, only for RAEGuardS LEL and IR
LO Low Alarm
HI High Alarm
Id Client ID
bAUd Baud rate. Supports 19200, 9600, or 4800
LItE Backlight
Aout Analog output 4mA and 20mA adjustment
tESt Test Function of LED, External Alarm, and 4-20mA

• To change a value, press [MODE] until the desired parameter
appears.

• Press [+] to enter the Process Menu.

• To increase a value, press [+].

• To decrease a value, press [-].

• When finished changing the value, press [MODE].

If a value has changed, the new value blinks on the LCD.

• Press [-] or [MODE] to discard changes and advance to the
next submenu item.

• Press [+] to save changes.

The “SAVE” message appears on the screen to confirm changes have
been saved.

26

RAEGuardS EC / LEL / IR User’s Guide

After entering the Advanced
Menu, step through the
parameters by pressing [MODE].
To edit a parameter, press [+].
The screen shows the current
reading value of the parameter.

You can exit Advanced Menu at
any screen by pressing [-]. In
addition, Advanced Menu is
automatically exited if you do not
make any changes within 60
seconds.

27

RAEGuardS EC / LEL / IR User’s Guide

This diagram shows how to edit parameter values and save changes
for most of the parameters:

28

RAEGuardS EC / LEL / IR User’s Guide

This diagram shows the submenu of parameters for the 4-20mA
Analog Menu:

29

RAEGuardS EC / LEL / IR User’s Guide

This diagram shows the submenu of parameters for the Test Menu:

* The analog output steps from 4mA to 20mA in 1mA steps and then
steps back down to 4mA before returning to the upper menu. Each
step is held for 3 seconds. Press any key to interrupt the process.

30

RAEGuardS EC / LEL / IR User’s Guide

2.6 Advanced Menu (IR)

The Advanced menu allows the user to change the values for each
reading and setup option. To access the Advanced menu from the

Reading Display, first press [+], [-],and then [MODE] in sequence.

Then scroll through the parameters shown below by pressing

[MODE].

Anytime a submenu screen is idle for more than 60 seconds, the
transmitter will return to the Reading Display.

Advanced Menu

Submenu LCD display Default

Standard gas
concentration

CO2: C5E3

(represents 5000 ppm)

CH

4

: C050

(represents 50% LEL)

CO

2

: C5E3

CH

4

: C050

Low alarm CO2: L4E3 (4000 ppm)

CH

4

: L020 (20% LEL)

CO

2

: L4E3

CH

4

: L020

High alarm CO2: H8E3 (8000 ppm)

CH

4

: H050 (50% LEL)

CO

2

: H8E3

CH

4

: H050

User ID IdXX Id00

Baud-rate
(kBaud)

B19.2, B09.6, B04.8
(19200, 9600, and 4800)

B09.6

4mA output
adjust

A04

20mA output
adjust

A20

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RAEGuardS EC / LEL / IR User’s Guide

To change a value, press [MODE] until the desired parameter
appears. Then press [+] to enter the Process Menu.

• To increase a value, press [+].

• To decrease a value, press [-].

Press [MODE] when finished changing the value. If a value has

changed, the new value blinks on the LCD.

• Press [-] or [MODE] to discard changes and advance to the next

submenu item.

• Press [+] to save changes. The “SAVE” message appears on the

screen to confirm changes have been saved.

2.7 Restoring Default Values (EC & LEL)

You can reset all values in the RAEGuardS EC and LEL to factory
default values. Follow this procedure:

1. Press [MODE] to Zero.

2. Press [MODE] to SPAN.

3. Press [MODE] key to show DEFT in the display.

4. Press [+]. The display flashes DEFT and awaits confimation.

5. Press [+] to Save the change. All data is cleared and the default

values are now restored.

32

RAEGuardS EC / LEL / IR User’s Guide

3. Theory of Operation

The RAEGuard

S

EC uses electrochemical sensors. The electrons

generated at the working electrode travel via the contact pins to be
measured at the external circuit and are returned to the counter
electrode to complete the circuit, The current of the sensor response
is proportional to the related EC sensors’ gas concentration.

The RAEGuard

S

IR is based on the patented technology of non-

dispersive infrared (NDIR) for hydrocarbon, carbon dioxide and other
gas detection. After sample gas diffuses into the infrared optical gas
sensor, the electro-magnetic radiation cause oscillation on gas
molecules. If this happens the oscillation reduces the amount of
radiation, it absorbs a certain degree of radiation. The absorbance at
specified wavelength is a measure of the present gas concentration.

The RAEGuard

S

LEL uses a highly poison-resistant catalytic bead

lower explosion limit (LEL) sensor. After sample gas diffuses through
the metal sinter into the combustion chamber, a pair of combustion
elements inside the combustion chamber burns the combustible gas
and generates an electrical signal.

The RAEGuard

S

is a microcontroller-based instrument. After the
electrical signal is conditioned and converted to digital, the
microcontroller processes the data, which displays the results locally
and reconstructs the digital data into a standard 4-20 mA analog
current output signal and RS-485 digital output signal.

The instrument has three magnetic sensing keys. The user may
calibrate the transmitter and change the alarm level setting via the
magnetic front-panel key pad.

33

RAEGuardS EC / LEL / IR User’s Guide

The instrument is powered by a DC power supply located in a safe
area. The power supply on the PC board contains a switching and
linear regulator that converts the main input voltage to 3.3V and 5V
DC to power the entire circuit.

34

RAEGuardS EC / LEL / IR User’s Guide

4. Maintenance

As a guide, it is recommended to regularly “bump test” a RAEGuardS
unit with a known percentage gas.

LCD

Main PCB

Enclosure Cover

Cable

Socket PCB

Enclosure Body

7R EC, LEL, or
NDIR Sensor

Holder

Exploded View of RAEGuardS EC and LEL Components

Periodically examine the sensor’s opening to make sure it is not dirty
or covered in dust or debris.

If the sensor requires replacement, refer this unit to qualified service
personnel.

35

RAEGuardS EC / LEL / IR User’s Guide

5. Troubleshooting

Note: Before diagnosing measurement problems, perform zero and

span calibration.

Symptom Reason & Solution

E001

Reason: Sensor not installed
Solution: Install the sensor

E002

Reason: Wrong sensor or Sensor

EEPROM error

Solution: Replace sensor

E003

Reason: Calibration failure
Solution: Make sure of standard gas flow

and perform recalibration

Replace Sensor

E004

Reason: EC sensor zero drift
Solution: Recalibration

E005

Reason: EC sensor exceeds max raw

count

Solution: Call RAE Systems technical

support

E006

Reason: Wire connection error
Solution: Check and reconnect wires

E007

Reason: Main PCB EEPROM error
Solution: Check and replace main PCB

Couldn’t turn

on the unit

Reason: Wrong position of one switch

(S3)

Solution: Check the position of switch S3

Reading

abnormally

High

Reason: Calibration failure
Solution: Recalibration
Eliminate/control source of

temperature difference

“Span failure”

signal

Reason: Sensor broken
Solution: Replace Sensor

Low 4-20mA

output

Reason: Power supply voltage is lower

than specified.

Solution: Check power supply voltage

and connection.

“Err”

Reason: Sensor ID is creating an error.
Solution: Check that the correct sensor is

installed. Replace the sensor or
update the firmware.

36

RAEGuardS EC / LEL / IR User’s Guide

Table A: EC Sensor configuration

The following table contains specifications for sensors in the
RAEGuard

S

EC Series.

Sensors Range

(ppm)

Resolution

(ppm)

Response

Time (T

90

)

Span

(ppm)

Low

(ppm)

High

(ppm)

CO 0-1000 1 <30s 50 35 200
H2S 0-300 0.1 <20s 25 10 20
SO2 0-150 0.1 <30s 5 2 10

NO 0-1000 0.5 <20s 25 25 50

NO2 0-50 0.1 <25s 5 1 10

Cl2 0-30 0.1 <30s 10 0.5 5

O2 0-30% 0.1% <20s 20.9% 19.5% 23.5%

ClO2 0-1 0.01 <120s 0.5 0.2 0.5

NH

3

0-100 0.5 <60s 50 25 50

PH3 0-20 0.05 <30s 5 1 2

HCN 0-100 0.5 <200s 10 4.7 50

ETO 0-100 0.1

<80s

37

RAEGuardS EC / LEL / IR User’s Guide

6. ModBus/RS-485 Information

Retrieving Gas Concentration Data From A RAEGuard

S

Via RS-485

The RAEGuard s communicates by means of MODBUS RTU. All

monitors provide a 4-byte register value. Note: Gas concentration is

the only value that can be retrieved.

As example be low 34 hex = 52 decimal

Overview

This document describes the modbus protocol used in RAEGuardS
products.

1. Communication Setting

Transmission MODE: RTU
Controller: PC or Controller
Client: RAEGuard

S

EC, LEL, IR
Baud Rate: 4800, 9600, 19200
Client ID: 1 to 99 (0x0001 to 0x0063), except for 58 (0x3A)

2. Message Frame/Communications Procedure

RAEGuardS EC/LEL/IR only support Function Code 0x03 (read
holding registers), which only supports the “Get Reading Value” from
the detector.

38

RAEGuardS EC / LEL / IR User’s Guide

39

0x03: Read Holding Registers
Requesting Message:

Device
Address

Func­tion
Code

Register
Address
High
Byte

Register
Address
Low
Byte

Quantity
of
Registers
High
Byte

Quantity
of
Registers
Low Byte

CRC
Low
Byte

CRC
High
Byte

Client ID 03 00 08 00 02 CRC CRC

Answering Message:

Device
Address

Function
Code

Byte
Count

Register Value CRC

Low
Byte

CRC
High
Byte

Client ID 03 04 Reading

Highest
Byte

Reading
Higher
Byte

Reading
High
Byte

Reading
Low
Byte

CRC CRC

Note: The length of data from the detector is 4 bytes.

Example:

Request: 01 03 00 09 00 02 14 09
Answer: 01 03 04 00 00 00 34 FB E4

Note: The maximum distance should be less than 1 km when using a

1.5 mm

2

cable.

P/N 033-4117-E00 Rev A August 2009