nimbus in detail

7/30/2019 Nimbus in Detail

1/13

Nimbus - in detail


2/13

How does Nimbus work?

Dual wavelength beam

- 3.3 and 3.05 microns

Detectors 1 & 2

light

Lamp windows cell gas sample chamber reflectors


3/13

Nimbus vrs. Cirrus

Lighter and less expensive

- Marine grade alloy - LM25, referred to as Copper free

Aluminum in the US

- Advanced electronic design uses single rigid PCB and

achieves even higher MTBF of 10 years Simplified optical design

- Custom IR detector block - reduces cost at the expense

of flexibility

Integrated Gas Cell- For simple gas checks

Dual 4-20 mA output


4/13

Nimbus PCB assembly

IR SourceIR Detectors

Main connections


5/13

Installation

Cable- 3-way 1mm2 to 2.5mm2.

- 4-way can be used for dual mA output

Supply

- 10V- 32V @ 180mA (constant current)

Power

- 2-6W, extra power is dissipated as additional heat into

the optics

Mounting

- Set orientation if mounted externally, or hosing may

occur


6/13

Orientation


7/13

Operation

Start-up

- Nimbus takes less than 10 seconds to start detecting

gas from power-up. Single green flash indicates normal

operation.

Rapid response to gas- Nimbus has a T90 of less than 7 seconds and will

respond to gas in less than 3

Status LED

- The operating state and a wide range of faults can bedetermined using the LED

- Green - Ok, Red - Gas, Orange - Fault


8/13

Modbus communications

Exd Comms connector fitted as standard

- Connects to PC or I.S. communicator, e.g. MTL611B

- Software for PC and MTL available now

- WindowsCE platforms will be supported

Read gas level, obscuration and faults

Set mA output levels

- Force mA output during commissioning

Perform zero and calibration

- Automated Wizards lead the user through these

processes


9/13

Wizards

Available with PC & MTL software

Guides the user

- The user is lead through the zero and calibration

process with a series of screens

- Inhibit functions are automatically applied allowing one-man-operation without panel inhibits

User selectable calibration gas concentration

- The software ensures an appropriate range is used

User & date stored

- After a successful zero or calibration, the user name

and date are stored in Nimbus


10/13

Supplied as Standard

Weather proof cover

- Static dissipative plastic to meet the new ATEXT

requirements

Single M20 or 1/2NPT Cable entry- 1 as standard, 2 can be requested at extra cost.

Communications port

- A flameproof optical communications portfor connection

to the I.S. cable. This is either M20 or 1/2 NPT tomatch the cable entry.


11/13

Accessories

Flow cover

- For calibration or gas testing

I.S. Cable + PC software

MTL611B

- Intrinsically safe hand held communicator

Data pack for MTL611B


12/13

Approvals

Full UL flameproof approval

- Nimbus meets UL1203 Class 1, Div 1, Groups B,C,D

- Cirrus meets UL2279 Class 1, Zones 1 & 2

Full CENELEC flameproof approval- EEx d IIB + Hydrogen T6

Full EMC approvals

- EN50081-2, EN50082-2 and prEN50270

IP and NEMA approvals

- IP66 (hosing) & IP67 (temporary submersion)

- NEMA 4X (US) - Includes Ice formation & salt spray


13/13

Future Developments

Gas cell calibration

WindowsCE support for rugged palm-tops and

alternative I.S. devices

Duct mounting kit

Addressable systems support (dual port)

nimbus in detail

Documents