Maintenance - Technical Manual...The Maintenance of the transmitter is described in the MM5006E...

Liquid Level Transmitter

CT801-SI, CT801-TA

Technical Manual

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Liquid Level Transmitter Technical Manual

CT801-SI, CT801-TA

1st Edition Released February 2013

TABLE OF CONTENTS

1. INTRODUCTION .............................................................................................................................. 4

2.DESCRIPTION .................................................................................................................................. 5

2.1 Pneumatic modulator .................................................................................................................. 6

2.2. Electric conditioner..................................................................................................................... 7

3. TECHNICAL SPECIFICATIONS ...................................................................................................... 8

4. OPERATION .................................................................................................................................... 9

5. INSTALLATION .............................................................................................................................. 10

5.1 Mechanical installation .............................................................................................................. 10

5.2 Air supply .................................................................................................................................. 11

5.3 Electrical connection ................................................................................................................. 11

5.3.1 CT801-SI ............................................................................................................................... 11

5.3.2 CT801-TA .............................................................................................................................. 12

6. PERSONAL NOTES ...................................................................................................................... 13

Doc No: MT5006E – Revision 4 – ENG Liquid Level Transmitter CT801-SI, CT801-TA Technical Manual 4

1. INTRODUCTION The Level Transmitter CT801 Series is designed for measuring the level of all types of liquid products in all kinds of tanks such as ballast tanks, service tanks,…, from the hydrostatic pressure of an air-flow bubbling through a pipe which reaches the bottom of the tank. This pressure is transmitted to an electronic conditioner including a pressure sensor, providing an electrical analog output signal.

Two models are available :

● CT801-SI, the standard model, providing an electric current from 4 to 20 mA in the 24 Vdc typical power supply loop. Two wires are necessary for the CT801-SI connection to the monitoring system.

● CT801-TA, designed for connection to a TA840 or EM940 Radar level transmitter : powered by the 5 Vdc source, the output signal is a voltage ranging from 0.5 to 2.5 Vdc connected to an analog input of the Radar. Three wires are necessary to connect the CT801-TA to the closest Radar transmitter, for cable saving.

These models are designed to be used in all hazardous area : the certificate is attached in annex A.

The CT801 Series are fitted with a differential pressure sensor, so even if installed on a pressurised tank, the output signal is a direct function of the liquid height.

The CT801 Series are fitted with the following mechanical interface, for the best adaptation to all installation conditions :

● Suffix B : flange PN16 DN50 ● Suffix R : female threaded coupling 1" BSPP, with optional bracket ● Suffix R1/4 : female threaded coupling 1/4" NPT, with optional bracket

The Installation of the transmitter is described in the MI5006E Maintenance Manual. The Maintenance of the transmitter is described in the MM5006E Maintenance Manual.


2. DESCRIPTION The CT801 Series is composed of two main parts : the pneumatic bubbling flow modulator and the electronic signal conditioner.

The operation principle is as follow :

Overpressure protection valve

Low reference pressure inlet

Outlet connection to a pressure indicator

(pressure copy)

Bubbling flow generator, with flow adjustment

Air supply inlet connection

Bubbling air return protection valve

Air supply filter

Pressure sensor on the electronic module

Bubbling outlet

Electronic module

Tank, the level of which to be measured

Non return valve

Flow control outlet


2.1 Pneumatic modulator The pneumatic bubbling flow modulator is common for both models. It is composed of :

Identification plate

Enclosure for the electronic conditioner

Overpressure protection valve

NPT 1/8" coupling for low reference pressure inlet connection (pressurised tank) or venting nipple (non-pressurised tank)

NTP 1/8" coupling for outlet connection to pressure indicator (pressure copy)

Bubbling flow generator, with air flow adjustment

NTP 1/4" coupling for air supply inlet connection

Bubbling air return protection valve

NTP 1/4" coupling for flow control

Process interface and outlet connection of the bubbling probe:

- Flange PN 16-DN 50 with threaded coupling 1/2" NPT

- Cylindrical 1’’ BSPP fitting. - Conical 1/4’’ NPT fitting

Air supply filter


2.2. Electric conditioner The electronic conditioner board, including the pressure sensor, is placed in a solid housing on top of the pneumatic modulator, ensuring the compactness of the CT801 transmitter.

Two kinds are available, one for model CT801-SI, one for model CT801-TA :

CT801-SI :

CT801-TA :

Terminals

Zero adjustment ("Z" mark)

Span adjustment ("S" mark)

Type 34052 Type 35445

Terminals

Zero adjustment ("Z" mark)

Span adjustment ("S" mark)


3. TECHNICAL SPECIFICATIONS ● Span : adjustable by potentiometers within the following ranges :

HYDROSTATIC PRESSURE

MEASURING RANGE ADMISSIBLE

OVERPRESSURE

0-50/70 mbar 350 mbar 0-70/350 mbar 1000 mbar

0-350/1050 mbar 3000 mbar 0-1050/2100 mbar 6000 mbar 0-2100/4100 mbar 10 000 mbar

● Power supply for model CT801-SI:

Type 34052 : 12 to 28 Vdc (nominal 24 Vdc), with resistive load from 0 ohms at 12 Vdc to 800 ohms at 28 Vdc

Type 35445 : 16 to 28 Vdc (nominal 24 Vdc), with resistive load from 0 ohms at 16 Vdc to 600 ohms at 28 Vdc

● Power supply for model CT801-TA:

5 Vdc supplied from TA840 or EM940 transmitter

● Output signal : current loop 4 - 20 mA for model CT801-SI

0.5 - 2.5 Vcc for model CT801-TA, toward TA840 or EM940 analog input

● Bubbling air supply : 4 to 10 bar, instrument quality (nominal 6 bar)

● Bubbling flow : 10 l/h, regulated

● Uncertainty : 0.3 % of nominal sensor range (linearity + hysteresis + repeatability)

● Temperature compensation range :

0 to +70°C

● Temperature drift : < 0.015 %/°C within the compensation range

● Operational temperature : -40°C to +85°C

● Storage temperature : -50°C to +85°C

● Time drift : 0.1% of nominal range, non cumulative

● Safety : II 1 G D Ex ia IIC T6 Ga (see also § 0 and 0)

Ex ia IIIC T70°C Da IP66/67

● Protection degree of enclosure : IP 66/67

● Material : all Brass

● Environment : acc. to IACS E10 Rev. 5, for installation on deck


4. OPERATION The bubbling flow of air from the CT801 is driven by a bubbling line to the bottom of the tank, at a level which is considered as the reference level, in order to meet the hydrostatic pressure of the liquid in the tank at that location. In the case of a pressurized tank, the pressure over the liquid surface is connected to the low pressure inlet of the CT801. So, the electric output signal of the CT801 transmitter is the direct function of the hydrostatic pressure of the liquid itself at the outlet of the bubbling line.

Then, the calculation formula for getting the level from the hydrostatic pressure measured by the CT801 transmitter is :

Measured Level "H" = (hydrostatic pressure) / 9.81 / density x 100000 + Zero Line "h" with :

● Measured level "H" in mm

● Pressure in mbar

● Density of the liquid in kg/m3

● Zero line "h" in mm is the distance between the extremity of the bubbling line and the tank bottom

In the case of a pressurized tank, the hydrostatic pressure is the pressure of the liquid at the outlet of the bubbling probe, minus the pressure over the liquid surface, connected to the low pressure inlet connection of the CT801 transmitter.

Thanks to the bubbling air process, the CT801 transmitter can be placed anywhere, even below or far from the tank, since its location has no influence on the measurement process : due to the regulated low flow, the pressure drop in the bubbling line is negligible, no matter the line profile.

Bubbling probe at the reference level

A

B Maximum level to be measured

H

h

Tank bottom

Reference level

Connection to the gas pressure over the liquid surface, if any


5. INSTALLATION

5.1 Mechanical installation Refer to the Installation Manual MI5006E.

The CT801 transmitter can be placed anywhere. Select the mechanical interface for best installation :

● Flange model "B" : for deck or floor installation; ● Female coupling "R" : for wall installation using the optional bracket and a 1" bubbling

line;

Female coupling "R1/4" : for wall installation using the optional bracket and a 1/4" bubbling line;

RECOMMENDATION: - It is strongly recommended to isolate the bubbling line by inserting a

valve for checking or maintenance purposes.

- In case of use with muddy fluids (for instance ballast tanks), or when particles are able to obstruct the bubbling line in the tank, a three-way valve should be inserted into the bubbling line, on the transmitter side, being supplied with compressed air : when the measuring signal increases, possibly due to a partial obstruction in the bubbling line, this valve should be switched so helping to dispose the suspect obstruction.

This valve can also be used to reduce the response time needed to reach the hydrostatic pressure equilibrium when starting the system.

CAUTION: - When the CT801 is installed at a place lower than highest liquid surface

level, it is essential to attach an isolating valve to the bubbling line in order to allow for the installation and removal of the transmitter, without any risk of liquid expansion.

This valve should be installed close to the transmitter, ensuring that a dead volume of 0.5 litre is preserved between the CT801 and the valve.

- The bubbling line must not show any low point, liable to retain liquid or condensation in the bubbling line.


5.2 Air supply Refer to the Installation Manual MI5006E.

● Connect the air supply to NPT ¼’’ inlet coupling marked with an arrow (see § 0).

5.3 Electrical connection Refer to the Installation Manual MI5006E.

5.3.1 CT801-SI 5.3.1.1 Supply voltage Supply voltage on the transmitter = 12 to 28 Vdc or 16 to 28 Vdc, to be determined according to the line impedance as shown on the following diagram:

The power supply to the transmitter is the main power supply minus the voltage drop of the Zener barrier if any.

5.3.1.2 Precautions for intrinsically safe installation Ex ia

RECOMMENDATION: Incorporate a valve into the supply circuit, for best installation and maintenance conditions

IMPORTANT NOTE: The CT801 transmitter must be supplied with instrument-quality air at a pressure of 4 to 10 bar. Do not hesitate to contact Honeywell Marine for the provision of an air dryer and oil extractor.

LOAD ohms

Power Supply Volts dc

800

400

12 20 28 Vdc

0

24

600

Type 34052 Type 35445


In particular, the supply source characteristics must comply with :

Ui (Vdc) Ii (mA) Pi (W)

£ 28 £ 120 £ 0.84 The result of such association is an intrinsically safe system, which must be certified. The certification is the responsibility of the associated device's provider.

As a consequence, a suitable Zener barrier must be installed in Safe Area, to be inserted into the line between CT801-SI and the power supply / measure acquisition device.

5.3.2 CT801-TA 5.3.2.1 Supply voltage The CT801-TA is designed to be powered by the 5 Vdc source from the Radar transmitter. The 0.5 to 2.5 Vdc output signal is connected to an analog input of this Radar transmitter.

5.3.2.2 Precautions for intrinsically safe installation Ex ia

In particular the supply source characteristics must comply with :

Ui (Vdc) Ii (mA) Pi (W)

£ 8 £ 540 £ 1.1

The result of such association is an intrinsically safe system, which is certified accordingly.

The CT801-TA transmitter, certified II 1 G D Ex ia IIC T6 Ga


under certificate n° LCIE 02 ATEX 6182X and IECEx LCIE 12.0005X, must be associated to an intrinsically safe certified device, complying with the transmitter's intrinsic safety parameters.

The internal capacitance Ci is £ 7.2 µF; the inductance Li is negligible.

IMPORTANT NOTE: The CT801-SI transmitter, certified II 1 G D Ex ia IIC T6 Ga


under certificate n° LCIE 02 ATEX 6182X and IECEx LCIE 12.0005X, must be associated to an intrinsically safe certified device, complying with the transmitter's intrinsic safety parameters.

The internal capacitance Ci is £ 17 nF; the inductance Li is negligible.


6. PERSONAL NOTES

Honeywell Marine SAS 9, Rue Isaac Newton 18000 Bourges France Tel + 33 (0) 2 48 23 79 01 Fax + 33 (0) 2 48 23 79 03 E-mail: [email protected] www.honeywellprocess.com

MT5006E-rev04-ENG February 2013 © 2013 Honeywell International Inc.

mailto:[email protected]





Maintenance - Technical Manual...The Maintenance of the transmitter is described in the MM5006E...

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