Crowcon TXgard-Plus Talimatlar

Gaz Dedektörleri Crowcon TXgard-Plus için çevrimiçi göz atın veya pdf Talimatlar indirin. Crowcon TXgard-Plus 5 sayfaları. Flameproof toxic and oxygen gas detector

Sayfayı Yazdır

Instructions

TXgard-Plus

Flameproof

Toxic and Oxygen

Gas Detector

with Non-intrusive One-man Calibration

1. INTRODUCTION

1.1 Product overview

TXgard-Plus is a flameproof toxic and oxygen gas detector

suitable for use in zone 1 or 2 hazardous areas. It is designed to detect

the following gases when fitted with the appropriate electrochemical

sensor:

Gas

Hydrogen sulphide

0–25 ppm

Carbon monoxide

0–250 ppm

Ammonia

0–50 ppm

Oxygen

0–25% vv

Sulphur dioxide

0–10 ppm

A local display and magnetically operated switches allow non-

intrusive one-man calibration without a hot work permit. Powered by

24 V dc (nominally) TXgard-Plus provides a 4-20 mA signal (sink or

source) proportional to the gas concentration and can also be fitted

with optional alarm and fault relays.

1.2 Product description

TXgard-Plus comprises four parts; 96HD sensor housing, junction box, amplifier

and terminal board. Diagram 1 details TXgard-Plus. The overall assembly is

certified EEx d IIC T6 in Europe and Class 1 , Zones 1&2 AEx d IIC T6 in the USA.

The 96HD sensor housing is a modular stainless steel assembly that

dismantles to allow plug-in sensors to be replaced easily (see Diagram 4). The

assembly screws into an M20 entry on the junction box.

The junction box is manufactured from marine grade alloy and is supplied

with 2 x M20 (1/2" NPT for USA) cable entries for customer use. Alternative cable

entries are available from Crowcon.

The amplifier plugs into the terminal board, and is held in place by two

captive screws. The amplifier provides power to the sensor, local display and

controls, and a 4-20 mA signal proportional to the gas concentration for connection

to a control panel. To remove, turn screws anti-clockwise and use them to pull

amplifier out of the enclosure.

All electrical connections are made via the terminal board mounted in the

base of the junction box (see Diagram 2). Optional alarm relays (AL1 & AL2) and one

fault relay (FAULT) are mounted on the terminal board which may be used to drive

local warning devices or connect TXgard-Plus to a control panel.

Range

Type

Toxic

Oxygen

Toxic

1.3 Status Indication

TXgard-Plus includes a local display and status LED, visible through

the junction box window, see Diagram 1. The display shows the gas

concentration and current mode of operation ie. NORMAL, ZERO or CAL.

The LED shows the current alarm state of the detector. This is summarised in

Table 1.

Operational

LED

state

indication

Normal

Steady green

operation

Normal

Steady red

operation

(alarm 1)

Normal

Flashing red

operation

(alarm 2)

Over-range

Flashing red

Zero/calibration

Flashing green

mode

Detector

Steady amber

fault

*See section 2 for AL1 and AL2 standard settings

Table 1: LED status indicator summary.

UNITS

M20 (

" NPT)

CABLE ENTRY

STEADY ON

INDICATES

ZERO/ CAL

MODE

ACTIVATED

"UP"

EXTERNAL

EARTH POINT

Diagram 1: TXgard Plus general arrangement

Relay

Comment*

states*

AL1 - Off

Gas level < AL1

AL2 - Off

Current output = 4–20 mA

FAULT - On

AL1 - On

AL1 < gas level < AL2

AL2 - Off

Current output = 4–20 mA

FAULT - On

AL1 - On

Gas level > AL2

AL2 - On

Current output = 4–20 mA

FAULT - On

AL1 - On

Gas level > full scale

AL2 - On

Display backlight flashes

FAULT - On

Current output = 24 mA

Configuration

Latched until reset by 'MENU'

dependent

Current output = 2 mA

(see section 2) (4 mA option)

AL1 - Off

Current output = 0 mA

AL2 - Off

FAULT - Off

115 (4

TXgard-Plus

ppm

83 (3

All dimensions in mm unless otherwise stated

Relay version only

TAMPER PROOF

GRUB SCREW

(1.5mm ALLEN KEY)

LOCAL

DISPLAY

M20 (

" NPT)

CABLE ENTRY

FLASHING

INDICATES

4-20mA/RELAYS

INHIBITED

ALARM 1 & 2

ADJUSTMENT

POTS

STATUS

LED

"DOWN"

4 OFF

FIXING HOLES

O 6mm (

HEIGHT = 115 (4