Crowcon TXgard Plus

Crowcon TXgard Plus Fixed Gas Detector

The Crowcon TXgard Plus is a flameproof (Ex d), ATEX, IECEx and UL certified toxic or oxygen gas detector with local LCD display. A choice of sensors are available enabling use in a wide range of applications, including water treatment, oil and gas exploration, chemical plants and steel production.


  • Non-intrusive one man calibration – easy to operate and maintain
  • Long life sensors – keeps interuption to on-site activity to a minimum
  • Simple parts replacement
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Please note - Product designs and specifications are subject to change without notice. The user is responsible for determining the suitability of this product.

Non-intrusive calibration

Calibration can be performed locally without the need for hot work permits – minimises operational down-time
Local display and buttons enable calibration without opening the junction box

Flexible output options

4-20mA current sink or source – works with a wide selection of control panels
3 wire format
Optional relays for alarm and fault – can be used for switching local alarms

Rugged and reliable

Constructed using marine-grade aluminium with a stainless steel sensor housing – proven track record for operation in the harshest environments
Ingress protection to IP65 as standard

Low cost of ownership

Non-intrusive one man calibration – easy to operate and maintain
Long life sensors – keeps interuption to on-site activity to a minimum
Simple parts replacement

Wide range of sensors
Carbon Monoxide, Hydrogen Sulphide and Oxygen range of electrochemical sensors available

Size 200 x 115 x 115mm (7.9 x 6.1 x 6.1ins)
Weight 2.2kg (4.9lbs)
Ingress protection IP65
Enclosure material Junction box: Marine grade alloy
Sensor housing: 316 stainless steel
Power 10-30Vdc, 210mA max (relay version)
160mA max (non relay)
Cable entries 2 x M20 or 1/2” NPT
Operating temperature -10°C to +55°C (-14°F to 131°F) *
Humidity 15 to 90% RH non-condensing
Relays (optional) SPNO or SPNC contacts rated
30Vdc 1A (non-inductive load) for Alarm 1, Alarm 2, Fault
Display 3-digit LCD back-lit display, LED status indicator
Calibration method Via magnetically operated buttons
Electrical output 3 wire 4-20mA, sink or source
Terminals Suitable for up to 1.5mm2 cable
Sensor type Electrochemical
Repeatability +/- 2% FSD typically
Zero drift +/- 2% FSD, 6 months typically
Response time Contact Crowcon for a full list of sensor response times
Performance Tested in accordance with EN60079-29-1
Hazardous area zones Zone 1 or 2
Approvals  Ex II 2 G
Ex db IIC T6 Tamb -20°C to +55°C
EMC compliance EN 50270, FCC: CFR 47 Part 15, ICES-003

* Figures shown exclude the sensors – Please contact Crowcon for a full list of sensor operating temperatures

Gases and Ranges

Gas Range Available
Carbon monoxide (CO) 100, 250, 500, 1000ppm
Hydrogen sulphide (H2S) 25, 50, 100, 200ppm
Oxygen (O2) 25% vol.


TXgard Plus Spares

C01697 Crowmag
M040013 Junction box lid O-Ring
S01866 Toxic gas amplifier, specify gas and range
S01867 oxygen amplifier
S01846/3 Analogue terminal board
S01847 Relay terminal board
S01892 Flamgard-Plus/Txgard-Plus junction box only (no label)
S01751 96HD/CO detector (spare)
S01750 96HD/HS detector (spare)
S01753 96HD/OX detector (spare)
S01752 96HD/AM detector (spare)
S01781 96HD replacement sinter
M01614 96HD sinter tool
S011182 Amplifier header: H2S 0-15ppm
S01855 Amplifier header: H2S 0-25ppm
S01856 Amplifier header: H2S 0-50ppm
S01977 Amplifier header: H2S 0-100ppm
S011156 Amplifier header: H2S 0-200ppm
S01857 Amplifier header: CO 0-100ppm
S01858 Amplifier header: CO 0-250ppm
S01859 Amplifier header: CO 0-500ppm
S011033 Amplifier header: CO 0-1000ppm
S01863/3 Amplifier header: O2 0-25%
S01891 TXgard Plus amplifier housing (includes mouldings, screws and labels, no PCB's)
S012124 96HD H2S detector head, ATEX markings only (no UL markings)

TXgard-Plus Exd Toxic and oxygen Gas Detector With Display

With relays

TXP-01 carbon monoxide 0-250ppm, relays, M20, ATEX
TXP-02 carbon monoxide 0-500ppm, relays, M20, ATEX
TXP-03 hydrogen sulphide 0-25ppm, relays, M20, ATEX
TXP-04 hydrogen sulphide 0-50ppm, relays, M20, ATEX
TXP-05 hydrogen sulphide 0-100ppm, relays, M20, ATEX
TXP-06 oxygen 0-25% vol, relays, M20, ATEX

Without relays

TXP-07 carbon monoxide 0-250ppm, no relays, M20, ATEX
TXP-08 carbon monoxide 0-500ppm, no relays, M20, ATEX
TXP-09 hydrogen sulphide 0-25ppm, no relays, M20, ATEX
TXP-10 hydrogen sulphide 0-50ppm, no relays, M20, ATEX
TXP-11 hydrogen sulphide 0-100ppm, no relays, M20, ATEX
TXP-12 oxygen 0-25% vol, no relays, M20, ATEX