ITSensor E2638-LEL Combustible Gas Detector Transmitter User Manual

ITSensor E2638-LEL Combustible Gas Detector Transmitter

Acetylene
A colorless flammable gas, lighter than air. Mixtures with air are explosive. It results from the interaction of calcium carbide with water. In industrial production, acetylene is mainly manufactured by the pyrolysis of light hydrocarbons. Acetylene is widely used for welding and cutting of metals. The usage of acetylene as a feedstock in the chemical industry declines due to cost and environmental considerations.

Synonyms/Trade Names: Ethine, Ethyne.

may have a garlic-like smell due to

impurities.

Hazards| Highly flammable. Gas/air mixtures are explosive. Forms explosive acetylide compounds with copper, mercury, silver & brasses (containing more than 66% copper).

Asphyxiant. Non-toxic, but, when generated from calcium carbide, it can contain toxic impurities such as traces of

phosphine and arsine.

Exposure limits (NIOSH)| REL C| 2662 mg/m3 /2500 ppm

Butane
A colorless flammable gas that is heavier than air. The term “butane” is used for any of two structural isomers (n-butane or iso-butane, with unbranched and branched-chain respectively) or for their mixture. Occurs in light petroleum fractions. Butane is used mainly as a fuel and as a feedstock in organic synthesis. It is applied also as a propellant in aerosol sprays and may be used as an ozone-friendly refrigerant. Mixtures of butane with propane and other hydrocarbons are referred to as LPG (liquefied petroleum gas).

narcosis, asphyxia, cardiac arrhythmia, fluctuations in blood pressure, and temporary memory loss, when abused directly from a highly pressurized container, and can result in death from asphyxiation and ventricular

fibrillation.

Exposure    limits (NIOSH)| TWA| 1900 mg/m3 /800 ppm| Not established

Hexane
A colorless flammable gas that is heavier than air. Hexane is a constituent component of gasoline. It is widely used in solvents as it is cheap, relatively safe and largely unreactive. It is also used as an industrial cleaner and degreaser and is an ingredient in many consumer products.

respiratory tract, cough, mild depression, cardiac arrhythmias.
Exposure limits| TWA| 1800 mg/m3 /500 ppm

Hydrogen
A colorless, odorless, flammable gas, that is much lighter than air. Mixtures with air are explosive. Results from the interaction of acids, bases, and water with active metals and from the electrolysis of aqueous solutions. In industrial production, the main source of hydrogen is hydrocarbons.

Asphyxiant.

Exposure limits| not established

Methane
A colorless flammable gas, the main component of natural gas, marsh gases. Methane results from bacterial decomposition of plant and animal matter (landfill gas). Methane is widely used as a fuel and chemical feedstock.

Synonyms: Marsh Gas, Natural Gas, Carbon tetrahydride, Hydrogen carbide.

contains an odorant

Hazards| Highly flammable, mixtures with air are explosive.

Asphyxiant.

Exposure limits| not established

Octane
A colorless flammable gas that is heavier than air. Octane is a component of gasoline (petrol).

respiratory tract, depression, and pulmonary edema.
Exposure    limits (NIOSH)| TWA| 350 mg/m3 /75 ppm

Propane
A colorless flammable gas that is heavier than air. it occurs in light petroleum fractions. Propane is used mainly as a fuel and as a feedstock in organic synthesis. It is applied also as a propellant in aerosol sprays and may be used as an ozone-friendly refrigerant. Mixtures of propane with butane and other hydrocarbons are referred to as LPG (liquefied petroleum gas).

contain odorant (“gas smell”).
Hazards| Highly flammable, mixtures with air are explosive. Asphyxiant. May cause dizziness, confusion, excitation

when inhaled.

Exposure limits (NIOSH)| TWA| 1800 mg/m3 /1000 ppm
IDLH| 2100 ppm [10%LEL]

Conversion of ppm to mg/m3 is calculated for 25°C and 1 atm.

• • according to new EU standards (‘stirred’ concentration of gas)
• ** according to US standard (‘still gas’ method)

Specifications

Detected gases| Acetylene, butane, hexane, hydrogen, methane, oxane, propane etc
---|---
Sampling method| Diffusion
Sensor type| Metal oxide semiconductor| Catalytic (pellistor)
Typical detection range| 0…100% LEL| 0…100% LEL
Resolution / digital unit| 0.1% LEL| 1% LEL
Response time T90| ca. 60 s| ≤10 s
Sensor lifetime| > 5 years| > 3 years
Calibration interval| 12 months| 6 months

Operating conditions

| -40…+70 °C| -10… +50°C
<95 % RH non-condensing, 0,9…1,1 atm Explosion-safe areas; normal ambient oxygen level

Avoid exposure to corrosive gases or silicon containing products

Signal update| Every 1 second

Power supply

| 12…36 VDC (default), 24 VAC or 230 VAC as options
Power consumption| < 2 VA
Analog outputs| 2 × 4-20 mA / 0-10 V, user settable
Outputs assignment| OUT1 gas; OUT2 gas

NOTE for LCD version only one output is available

Output scale width| > 10 × resolution Recommended: 20-100% of the detection range
Load resistance| RL < (Us – 2 V) / 22 mA for 4-20 mA

RL > 250 kOhm for 0-10 V mode

Digital interface| RS485, Modbus RTU protocol; No galvanic isolation
Enclosure| Grey ABS, wall mount, protection class IP65

Dimensions

| H90 × W145 × D55 mm

(overall dimensions H140 × W145 × D55 mm)

CE marking

| ****

According to 2014/30/EU and 2014/35/EU, EN 50491-4-1:2012 EN 61000-6-3:2020, EN 61326-1:2013(EMC, emissions) EN 61000-6-1:2019, EN 61000-6-2:2019(EMC, Immunity)

EN 60079-29-1:2016, EN 60079-29-2:2015 and EN 60079-29-3:2014

Relay option

Output relays| 2 × SPST relays (closing contact), 250 VAC / 30 VDC, 5 A max
Default alarm setpoints| RE1 (LOW): set 20% LEL; release 16% LEL RE2 (HIGH): set 50% LEL; release 40% LEL
Signalling options
Visual| Red and green LEDs
Acoustic alarm| Buzzer 85 dB
LCD indicator option
Operating temperature| 0…+50 °C
Display dimensions| 72 × 36 mm
Number of digits| 3.5, 7-segment
Character height| 14 mm
Other features| Backlight
Other options

Remote probe

| Protection IP65, default cable length 3.0 m; max height 80 mm, max diameter 65 mm

Product description

E2638 series detectors-transmitters belong to the PluraSens® family of multifunctional measurement instruments. The instruments utilize gas sensors of various types with excellent repeatability, stability, and long lifetime. E2638 series provides two independent analog outputs OUT1 and OUT2, user- selectable to 4-20 mA or 0-10 V, proportional to gas concentrations. RS485 Modbus RTU digital communication interface allows easy instrument configuration and integration into various automation systems.

The following features are available as an option:

• Two relays RE1 and RE2 with closing contacts. Relay outputs can be used to switch alarm sirens, ventilation fans, shut-off valves, or other actuators,
• Acoustic (85 dB buzzer) and visual (red and green LED) signaling,
• 24 VAC or 230 VAC as options for power supply module,
• LCD indicator,
• Remote probe.

The version of your device is marked on the package. If the symbol ⚠️is marked on the equipment, consult the documentation for further information.

Safety requirements

• Misuse will impair the protection of the product. Always adhere to the safety provisions applicable in the country of use.
• Do not perform any maintenance operation with the power on. Do not let water or foreign objects inside the device.
• Removal of the PCB from the enclosure voids the warranty. Do not touch the electronic components directly, as they are sensitive to static electricity.
• Connection diagrams can be found in the electrical connections section. The device might not perform correctly or be damaged if the wrong power supply is connected.
• External circuits connected to the equipment should have sufficient insulation rating according to the environmental conditions and equipment power.
• A disconnecting device that is marked as such and easily accessible should be included in the installation of this product.

Operating conditions
The device should be used both in a non-hazardous area and in a basic electromagnetic environment, where the latter is defined in EN 61326-1. Avoid strong mechanical shock and vibrations. Avoid corrosive atmosphere and areas highly contaminated with dust, oil mist, etc. Keep the instrument away from direct sunlight. A sudden temperature or humidity change might affect the sensitivity of the sensor.

Installation guidelines

Before proceeding with the installation it is mandatory to read the Safety requirements section and make sure to comply with all listed instructions. Installation standards EN 60079-29-2 and EN 45544-4 are also recommended for further instructions and related information about the installation. During the installation of the detector-transmitter the following points must be considered:

• Application (air quality control or leakage detection)
• Properties of the space under investigation (room geometry, direction, and velocity of airflows, etc.),
• For gases lighter than air install the sensor higher than the potential leakage/generation source or near the ceiling. Combustible gases lighter than air are hydrogen, methane, and acetylene. Propane, hexane, octane and butane are heavier than air and tend to sink. It is recommended to place the sensor lower than potential leakage or generation source.
• The device should be accessible for maintenance and repair.

The aforementioned conditions above will affect the coverage area of the device. however, the coverage area for a transmitter is usually between 2.5 to 5 meters radius. For early leakage detection install the sensor as close as possible to the potential leakage sources (flanges, valves, pressure reducers, pumps, etc.), taking into consideration other points listed above. For general area monitoring without definite leakage sources, the detectors should be distributed evenly in the room. For personal safety control, the detectors are installed in the breathing zone (at the height of the head of people or animals). The recommended sensor position is vertical, pointing downwards. For installing the device, attach the device to the wall using provided screws through the side mounting holes or key slots (see mountains dimensions).

Mounting dimensions

Front view

Bottom view

Sensor probe handling
The E2638 series devices are available with a remote probe. The remote probe is connected to the main unit with a shielded cable. The default remote probe cable length is 3 m.

A) Wall mount remote probe with fixing clamp (default version),
B) Remote probe with rubber flange and three self-tapping screws (on request)

The sensor probes of all types are equipped with a hydrophobic microporous PTFE filter to protect the sensor from dust, dirt, and water drops. The filter should be replaced if it gets strongly contaminated. To replace the PTFE filter, unscrew the sensor head cap and remove the old filter. Place a new filter into the cap and tighten it again.

NOTE! Never stab or press the filter near its center where the sensor is located since this may damage the sensor. Do not remove the filter as it may cause the device to show incorrect values and/or break the sensor. The recommended orientation of the sensor probe is vertical with the sensor tip pointing downwards. This prevents the possible accumulation of condensed water on the sensor protection filter.

Gas sensor replacement procedures

1. Remove the sensor head cap from the device (or the remote probe),
2. Remove the PTFE filter (if it is not removed within the cap),
3. Remove the O-ring rubber,
4. Detach the pellistor (catalytic) sensor from the device,
5. Insert the new pellistor (catalytic) sensor inside,
6. Put back the O-ring rubber, PTFE filter, and the head cap, respectively.
   NOTE! Metal oxide semiconductor sensors are not replaceable!

Electrical connections

Unscrew four lid screws and detach the lid from the device. Use two M16 cable glands to let in the cables of the power supply and of the external devices. Without turning on the power, plug the power cable, and connect the analog/relay outputs and/or digital interface terminals to the necessary devices according to the relevant connection diagram.

J u m p e r s

J1| OUT1 type (open: 4-20 mA; closed 0-10 V)
J2| OUT2 type (open: 4-20 mA; closed 0-10 V)
X6| Reset Modbus network parameters to default
X4 terminals
OUT1| 4-20 mA / 0-10 V output
OUT2| 4-20 mA / 0-10 V output
0V| 0 V / 24 VAC Neutral (optional)
A| RS485 A / Data +
B| RS485 B / Data –
+U| +24 VDC / 24 VAC Phase (optional)
X5 terminals (optional)
L| 90…265 VAC Phase
N| 90…265 VAC Neutral
RE1 NO| Relay 1, normally open terminal
RE1 COM| Relay 1, common terminal
RE2 NO| Relay 2, normally open terminal
RE2 COM| Relay 2, common terminal

The screwless quick connect spring terminals on the E2638 series devices are suitable for a wide range of wires with a cross-section of 0.2…1.5 mm2. We recommend striping the wire end by 8…9 mm and using wire end sleeves. To connect the wire, insert the wire end into the terminal hole. To disconnect, push the spring-loaded terminal lever, pull the wire out, and release the lever. Use a twisted-pair cable, e.g. LiYY TP 2×2×0.5 mm2 or CAT 5, to connect the device to the RS485 network. A and B on the device represent DATA+ and DATA- respectively, polarity must be respected when connecting to an external RS485 network. Both analog outputs can be independently changed between 4-20 mA and 0-10 V type using jumpers J1 (OUT1) and J2 (OUT2). By closing pins on a specific jumper the related output is 0-10 V, with an open jumper the output is 4-20 mA. Power restart is required after changing the position of the jumpers.

NOTE! The outputs are not galvanically isolated from the external power supply and share a common 0V. Allowed load resistance limits are stated in the Specifications table. To power the instrument from an external power source, connect terminals 0V and +U to the source. If the integrated mains power supply module is used, connect terminals L and N to the mains.
NOTE! Actuator short-circuits should be avoided, to protect the instrument relays, use external fuses or safety switches.

Correct and incorrect cabling for 24 VAC

Operation

Turn on the power. The instrument warm-up time for both types of sensors takes about 5 minutes after switching on and final sensor stabilization time to maximum accuracy takes about 1 hour. The operating status is indicated by the LED on the PCB of the device. The control LED (red) response to different processes is presented in the following table:

0.5 Hz (50% on, 50% off)

Relay 1 turned on| Blinking 1 Hz (50% on, 50% off)
Relay 2 turned on| Blinking 2 Hz (50% on, 50% off)
During Modbus communication cycle| Short on-off pulses
Normal operating/measurement| Continuously on or off

Make sure that the detector-transmitter is properly mounted, the external devices connected, power LED (green) on and control LED (red) constantly lit. Place the lid back and fix it with the screws. The device is ready to use.

Maintenance
Do not perform any maintenance operation with the power on. Clean the device with a soft damp cloth. Do not use any abrasive cleaning agents. Do not immerse the device in water or any cleaning media.

Calibration
E2638-LEL devices have been calibrated by the Manufacturer with standard gas mixtures before delivery. Provided that the sensor is used under moderate conditions, the recommended recalibration interval for the metal oxide sensor is 12 months. Catalytic sensors are more sensitive to the environment and require field recalibration every 6 months. Please contact your dealer for more information.

Delivery set

• Detector-transmitter E2638
• Mounting accessories:
  • 4 screws with plastic dowels
  • Fixing clamp for remote probe version

Order code for E2638-LEL options

E2638-LEL-RLCD3
Two SPST relays| E2638-LEL-R
Two LEDs (visual alarm)| E2638-LEL-LED
Buzzer (acoustic alarm)| E2638-LEL-B
Self-test button for relays| E2638-LEL-TB
Integrated coreless micropump| E2638-LEL-MP

Configuring

A standard configuration kit includes a USB-RS485 converter, fixed flow regulator, gas tubing with applicators, and a software pack. Please contact your Seller for more information. Detectors-transmitters E2638 share all functionalities of the PluraSens® multifunctional platform. The features and options include:

• Digital output change rate-limiting filter
• Digital integrating (averaging) filter
• Free assignment of each analog output to the chosen parameter
• Flexible setting of analog output scales for each output
• Output zero and slope adjustment for calibration
• Free assignment of each of two relays to the chosen parameter
• Several relay control logic modes
• Switch delays and minimum on/off state durations for each relay.

The output scales can be changed by Modbus commands by using the configuration software and the standard configuration kit (see Modbus RTU Communication).

Return to default settings
To reset the device’s Slave ID, baud rate, and stop bit numbers to factory settings, proceed as follows:

1. De-energize the device
2. Connect the X6 jumper
3. Turn on the device
4. De-energize the device
5. Disconnect the X6 jumper
6. Turn on the device

NOTE! Cables should be connected/disconnected from PCB when the power supply is unplugged. Connecting or Disconnecting Live wires can result in Corrupt Firmware.

Modbus RTU Communication

Communication parameters

Modbus functions

| 03 – Read multiple registers 06 – Write a single register

Error codes

| 01 – Illegal function

02 – Illegal data address 03 – Illegal data value 04 – Slave device failure

(details of last error 04 can be read from register 0x0008)

Modbus holding registers
Register addresses are shown 0-based, Address in hexadecimal, Reg in decimal format. Modbus holding register numbers MHR are shown in the decimal 1-based format and may be addressed either from 00001 or 40001 base.

Address| Reg / MHR| RW| Description| Supported values (dec)| Default
---|---|---|---|---|---
0x0001| 1 / 40002| R| Hardware version|  | –
0x0002| 2 / 40003| R| Software version|  | –
0x0003| 3 / 40004| R| Product serial number| 1…65535| –
0x0004| 4 / 40005| RW| Slave ID (net address) *| 1…247 **| 1

0x0005

|

5 / 40006

|

RW

|

Baud rate *

| 1200, 2400, 4800, 9600, 19200,

38400, 57600

|

9600

---|---|---|---|---|---
0x0006| 6 / 40007| RW| Response delay, ms| 1…255| 10

0x0007

|

7 / 40008

|

RW

|

Stop bits, parity bit *

| 1 – No parity bit, 1 stop bit (default after factory reset) 2 – No parity bit, 2 stop bits 3 – Odd parity, 1 stop bit

4 – Even parity, 1 stop bit NOTE : 3 and 4 are available starting from the Software version 0x218 (dec. 536)

|

1

0x0008| 8 /40009| R| Last error code| 1…255| –

0x0011

|

17 / 40018

|

RW

| Technological:

age of last data in seconds (read) / restart (write)

| 0…65535 s (read),

writing 42330 restarts the instrument

|

–

0x00A5

| 165 /

40166

|

RW

| Zero adjustments for gas data, ADC|

-32000…+32000 ADC units

|

0

---|---|---|---|---|---
0x00A6| 166 /

40167

| RW| Slope adjustment for gas data| 1…65535| 512
0x00A7| 167 /

40168

| RW| Change rate limit for gas units/ s| 1…32000, 0 – no limit| 0

0x00A8

|

168 /

40169

|

RW

|

Integrating filter time constant, s

|

1…32000 (seconds), 0 – no filter

|

0

Address| Reg / MHR| RW| Description| Supported values (dec)| Default

0x00C9

|

201 /

40202

|

RW

|

Parameter tied to analog output 1

| 0 – None

2 – Gas concentration

9 – Forced Modbus control, value set in MHR / 40204

|

2

0x00CA

|

202 /

40203

|

RW

|

Parameter tied to analog output 2

| 0 – None

2 – Gas concentration

9 – Forced Modbus control, value set in MHR / 40205

|

2

0x00CB

|

203 /

40204

|

RW

|

Forced value for analog output 1***

| 0…1000

(0.0%. 100.0% of output

scale)

|

0

0x00CC

|

204 /

40205

|

RW

|

Forced value for analog output 2***

| 0…1000

(0.0%. 100.0% of output

scale)

|

0

0x00D3

|

211 /

40212

|

RW

|

Parameter tied to relay RE1

| 0 –none

2 – gas concentration 9 – control by Modbus

control, state set in MHR / 40214

|

2

---|---|---|---|---|---

0x00D4

|

212 /

40213

|

RW

|

Parameter tied to relay RE2

| 0 – none

2 – gas concentration 9- – control by Modbus

control, state set in MHR / 40215

|

2

0x00D5| 213 /

40214

| RW| Forced state for relay RE1***| 0 –off, 1 – on| 0

0x00D6

|

214/ 40215

|

RW

| Forced state for relay RE2***|

0 – off, 1 – on

|

0

0x00D7| 215 /

40216

| RW| Switching delay for relay RE1| 0…1000 (s)| 0

0x00D8

| 216 /

40217

|

RW

| Switching delay for relay RE2| 0…1000 (s)|

0

0x00D9| 217 /

40218

| RW| Minimal on/off time for relay RE1| 0…1000 (s)| 0

0x00DA

| 218 /

40219

|

RW

| Minimal on/off time for relay RE2| 0…1000 (s)|

0

Address| Reg / MHR| RW| Description| Supported values (dec)| Default
---|---|---|---|---|---
 |  |  |  | |

0x00DB

| 219 /

40220

|

RW

|

Control logic for relay RE1

| 0 – none

1 – relay on at high values 2 – relay on at low values

|

0

 |  |  |  | 3 – relay on at values within|
 |  |  |  | the range|
 |  |  |  | 4 – relay on for the values out|
 |  |  |  | of the range|

0x00DC

|

220 /

40221

|

RW

|

Control logic for relay RE2

|

0 – none

1 – relay on at high values 2 – relay on at low values

3 – relay on at values within the range

4 – relay on for the values out of the range

|

0

---|---|---|---|---|---

0x00DD

| 221 /

40222

|

RW

| LOW setpoint for relay RE1|

0…65535 (gas units)

| see Specifications

0x00DE

| 222 /

40223

|

RW

| HIGH setpoint for relay RE1|

0…65535 (gas units)

|

see Specifications

0x00DF

| 223 /

40224

|

RW

| LOW setpoint for relay RE2|

0…65535 (gas units)

| see Specifications

0x00E0

| 224 /

40225

|

RW

| HIGH setpoint for relay RE2|

0…65535 (gas units)

| see Specifications

0x00FF

|

255 /

40256

|

RW

|

Sensor, analog outputs, LED and buzzer status

| bit[0]=0/1 – sensor present/absent, RO bit[1]=0/1 – analog outputs deactivated/activated bit[2]=0/1 – in case the sensor is absent, turn signaling off/on analog output1

bit[3]=0/1 – in case the sensor is absent, turn on signaling with low current/high current on analog output1; if bit[2]=0 this bit will be ignored

bit[4]=0/1 – in case of sensor absent, turn signaling off/on analog output2

bit[5]=0/1 – in case of sensor absent, turn on signaling with low current/high current on analog output2; if bit[4]==0 this bit will be ignored bit[6]=0/1 – current/voltage output detected on output1, RO

bit[7]=0/1 – current/voltage output detected on output2,

|
 |  |  |  | RO

bit[8]=0/1 – LED

deactivated/activated bit[9]=0/1 – buzzer deactivated/activated bit[10]=0/1 – LED is on/off in normal condition bit[11]=0/1 – 1 Hz (50% on, 50% off) LED signal off/on if relay1 turned on

bit[12]=0/1 – 2 Hz (50% on, 50% off) LED signal off/on if relay2 turned on

|
---|---|---|---|---|---
0x0101| 257 /

40258

| R| Raw gas sensor data| 0…4095, ADC units|
0x0103| 259 /

40260

| R| Gas concentration, gas units| 0…65535, gas units|
0x0105| 261 /

40262

| RW| 0% value

for analog output 1

| -32000…+32000, gas units| User defined
0x0106| 262 /

40263

| RW| 100% value

for analog output 1

| -32000…+32000 , gas units| User defined
0x0107| 263 /

40264

| RW| 0% value

for analog output 2

| -32000…+32000, gas units| User defined
0x0108| 264 /

40265

| RW| 100% value

for analog output 2

| -32000…+32000, gas units| User defined

• The new value is applied after restart.
• Broadcast slave ID 0 can be used to assign a new ID to the instrument with an unknown ID. When addressing by ID 0 the device shall be the only Modbus instrument in the network. The device will not respond to the Master command when addressed by ID 0.
• This value is dynamic and not kept in EEPROM after a restart.

Warranty

This product is warranted to be free from defects in material and workmanship for a period of one year from the date of the original sale. During this warranty period, the Manufacturer will, at its option, either repair or replace a product that proves to be defective. This warranty is void if the product has been operated in conditions outside ranges specified by the Manufacturer or damaged by customer error or negligence or if there has been an unauthorized modification.

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