Contrec 220 User Manual

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Page 1

LEVEL MONITOR

MODEL 220

June 2017

220-M-V3.1

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CONTENTS

1. Introduction 1

1.1 Model Number Designation 2

1.2 Intrinsic Safety Approvals 3

2. Specification 4

3. Operation 6

3.1 Display 6

3.1.1 Level Bar Graph 6

3.1.2 Contents 7

3.2 Front Panel Operation 8

3.2.1 Displaying Data 8

3.2.2 Changing Data 11

3.2.3 Timeout Condition 12

3.3 Test Mode 12

3.4 Alarms 13

3.4.1 Types of Alarms 14

3.4.2 Alarm Deadband 15

3.4.3 Alarm Action 15

3.4.4 Setting Alarms 17

3.5 Non-Linearity 18

3.6 Filtering 22

3.7 Density Correction 24

4. Programming 26

4.1 Program Steps 27

5. Signal Input 30

6. Alarm Outputs 31

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7. Installation 33

7.1 Wall Mounting 33

7.2 Panel Mount Version 34

7.3 Removing the Front Panel 35

7.4 The Main Electronics 37

7.5 Wiring 38

7.6 Maintenance 38

7.7 Terminal Designations 39

8. Intrinsic Safety Connections 40

Index 42

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Introduction

1. INTRODUCTION

The Model 220i Level Monitor is a microprocessor based instrument

which accepts a 4-20mA input and displays level and contents. It is powered entirely from the 4-20mA loop and, therefore, does not require an external power source.

Level is displayed in a bar graph as 0...100%. The contents are a 7 digit numeric display which can be spanned in any engineering units.

The instrument is fully programmable; the user can program alarm settings,

span & zero levels and non-linear correction points. Calculation constants are also set from the front panel and are stored in a non-volatile memory which retains data indefinitely.

The Model 220i Rate Totaliser conforms to the EMC-Directive of the Council of

European Communities 2004/108/EC, the LVD directive 2006/95/EC and the following standards:

EN61326:2013 Electrical equipment for measurement, control

and laboratory use – EMC requirements :

Residential, Commercial & Light Industry Environment & Industrial Environment.

EN61010:2010 Safety requirements for electrical equipment

for measurement, control, and laboratory use.

In order to comply with these standards, the wiring instructions in Section 7.5 must be adhered to.

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Introduction

1.1 MODEL NUMBER DESIGNATION

The Model Number of the 220i describes the input and output options installed

and the mounting options.

220 i . 2 M

Model Mounting 220i Intrinsically Safe 1 Panel mount

version 2 Wall mount

6 2" pipe bracket

Approvals

C CSA USA/Canada approval

M ATEX/IECEx approval

Tank Conversion Software

220CSW

Page 7

Introduction

1.2 INTRINSIC SAFETY APPROVALS

The Model 220i is certified for use in hazardous areas and has IECEx, ATEX

and CSA US/C approvals.

The Model 220i certification details are:

IECEx Approval IECEx BVS 15.0099X Rating Ex ia IIB T4 Gb

ATEX Approval BVS 15 ATEX E 106 X

Rating II 2G EX ia IIB T4 Gb

Ambient Temperature: Maximum ambient temperature of 60°C.

CSA U S/C Approval LR 104 840-5.

Type: Class 1, Groups C and D.

When installing in hazardous areas, the instrument will have to be

installed according to the guidelines given in Section 9 and in accordance with standards for wiring and installation in hazardous areas.

4-20mA Input

The input can be connected to IS circuits with the following maximum

values:

Ui = 28V Ii = 93mA Pi = 653mW

Relay Outputs

The outputs can be connected to IS circuits with the following

maximum values:

Ui = 28V Ii = 93mA Pi = 653mW

Page 8

Specification

2. SPECIFICATION

General

Display: Continuously powered LCD. Level: 30mm bar graph.

Level Span: 0...100% per full scale. Contents: 7 digit with 4½ digit resolution, 12mm (0.5") high. Contents Span: The units of measure (eg. litres) at full scale

of input signal. The contents span is programmable in the range of 0.000...9,999,999.

Volume: Either "V olume" or "Contents" can be

displayed.

This is user programmable.

Decimal Points: Decimal point positions for contents

is programmable in range of 0...3

decimal points.

Signal Type: 4-20mA.

4-20mA

Resolution and Linearity: 0.05% of span.

Accuracy: 0.05% of span @ 25°C.

0.1% (typically) of span full temperature range.

Update Time: 0.5 second. Connection: 2 wire.

Voltage Drop: 2.5V maximum.

Outputs

Type: 4 open collector output alarms suitable for

driving dc solenoids or external relays. The

outputs

provide:

1. high-high.

2. high.

3. low.

4. low-low. Switching Power: 200mA. 30Vdc maximum. Saturation V oltage: 0.8Vdc across the output in the "on" state. Isolation: All outputs are separately opto-isolated.

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Specification

Physical

Operating Temperature: -20°C to 60°C.

Dimensions: 97mm (3.8") high x 150mm (5.9") wide x 41mm (1.6") deep (not including cable glands).

Protection: Nema 4X or IP67 standards.

Cable Entry: Cable glands.

Mounting: Universal mounting bracket is supplied as standard.

Pipe Mounting: A galvanised metal bracket is available which

enables the instrument to be mounted on a 2"horizontal or vertical pipe.

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Operation

3. OPERATION

The Model 220i Level Monitor accepts a 4-20mA input signal from a level

sensor such as a pressure transmitter, ultrasonic sensor or capacitance probe.

The instrument is powered entirely from the loop and, therefore, requires no

external power or internal batteries.

The instrument is fully programmable with all operating parameters

and calculation constants programmable from the front panel (see Section 4.1). The setup parameters are stored in a non-volatile memory and are retained for at least 10 years in the event of a power loss.

3.1 DISPLAY

The display of the Model 220i comprises of:

Level Bar Graph

Contents

3.1.1 Level Bar Graph

The level bar graph displays the vertical level

of liquid as a percentage.

Inputs of 4mA and 20mA can be programmed to correspond to 0% and 100% respectively, or can be inverted so that 4mA will correspond to 100% and 20mA will correspond to 0%.

Note that the level is corrected for density (if applicable) as described in Section 3.7.

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Operation

3.1.2 Contents

The contents is a 7 digit numeric display where the span can be

programmed during setup to read in any engineering units. The contents are displayed with 4½ resolution in respect to the maximum contents.

For example, if the maximum contents is 1234567, the display will show up to 5 digits plus trailing zeros. At different inputs the following will be displayed:

1234567 will be displayed as 1234500; 234567 will be displayed as 2345000.

However, if the first digit is greater than 1, then up to 4 digits only will be displayed with trailing zeros. For example, if the maximum contents is 2345678, then at different inputs:

2345678 will be displayed as 2345000; 345678 will be displayed as 345000.

CALCULATION OF CONTENTS

For a linear tank the contents is calculated as follows:

Contents = (Span) x (% Level) + Offset

Transmitter

OFFSET

% LEVEL

SPAN

Zero

Contents

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Operation

3.2 FRONT PANEL OPERATION

3.2.1 Displaying Data

The alarm setpoints and density correction factor can be viewed by pressing

the DISPLAY key.

Key action What you will see What this means

If there are flashing alarms on the display they will stop flashing.

Acknowledges alarms if

alarms are flashing on the display.

High-high alarm.

The value of the high-high

alarm.

The high-high alarm

setpoint as a % of maximum level or contents value.

High alarm.

AL-HH

AL-HI

DISPLAY

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Operation

Key action What you will see What this

The value of the high alarm.

The high alarm setpoint

as a % of maximum level or contents value.

Low alarm.

The value of the low alarm.

The low alarm setpoint

as a % of maximum level of contents value.

Low-low alarm.

The value of the low-low

alarm.

The low alarm setpoint

as a % of maximum level or contents value.

AL-LO

AL-LL

DISPLAY

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Operation

Key action What you will see What this

Density correction

The value of the density

correction factor.

A factor for those

applications where the density of the fluid in

the tank is likely to change (default of

1.000).

Returns to contents display.

DISPLAY

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Operation

3.2.2 Changing Data

Each of the above parameters can be changed as follows:

1. Pressing the DISPLAY key consecutively until the numeric value of the parameter to be changed appears (as described in the previous diagram).

2. This value can then be changed using the following keys:

This key steps from digit to digit, causing the

digit to flash. Only flashing digits can be changed.

This key increments the flashing digit.

Example.

To change the high alarm setpoint to 75:

1. Press DISPLAY until the value of the high alarm appears. This will be

the value after AL-HI.

2. The first digit is flashing, this means it can be changed. Using

the key, this digit is changed to 7.

3. The key is pressed so that the second digit flashes.

4. Using the key, this digit is changed to 5.

Note that the Model 220i can be programmed so that the above parameters cannot be changed, see Section 4.1.

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Operation

3.2.3 Timeout Condition

Upon entering the display mode, if no key is pressed for 10 seconds, the display returns to the contents display with alarm acknowledgment cleared.

3.3 TEST MODE

The 220i has a test mode which can be entered by simultaneously pressing

all 3 front panel keys. There are 3 tests:

Low Test By pressing the key, the low and low-low

alarms outputs will be energised.

High Test By pressing the key, the high and high-high

alarm outputs will be energised.

Display Test By pressing the DISPLAY key, all segments of the

display will flash.

To exit the test mode all three keys are pressed simultaneously.

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Operation

3.4 ALARMS

The Model 220i has 4 alarm outputs:

The alarms can be assigned to level or contents which is done

during programming (see Section 4.1). Each alarm is individually programmed as a percentage (0-100%) of level or contents.

All of the alarms have open collector outputs and are separately isolated via

opto-isolators. The outputs are internally protected against voltage spikes caused by relays and coils.

High-High (HH)

High (H)

Low (L)

Low-Low (LL)

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Operation

3.4.1 Types of Alarms

3.4.1.1 Alarm Output

The Model 220i can be programmed for the alarm outputs to operate in one of

two ways:

1. the alarm outputs can energise (switch on) during an alarm condition, or

2. the alarm outputs can de-energise (switch off) during an alarm condition.

3.4.1.2 High Alarms

The high alarms will be activated when the contents or level in the tank

increase above the high alarm setpoints. These alarms will be deactivated when the contents or level falls below these programmed setpoints.

When setting the alarms, the high-high alarm should be set higher than the

high alarm.

3.4.1.3 Low Alarms

The low alarms will be activated when the level or contents in the tank falls

below the low alarm setpoints. These alarms will be deactivated when the level exceeds the programmed setpoint.

Similarly, when setting the low alarms, the low-low alarm should be set below the low alarm.

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Operation

3.4.2 Alarm Deadband

To prevent an alarm toggling on and off when the level is close to the

setpoint, a user programmable deadband is provided. The deadband is a percentage (0-100%) of the maximum level or contents.

Example 1.

If the low alarm is set to 20% and the deadband is set to 5%, the alarm will be activated when the level reaches 20%. The alarm will then stay activated until the level increases above 25%.

Example 2.

If the high alarm and deadband are set at 80% and 5% respectively, the alarm will be activated at 80% and will stay activated until the level falls below 75%.

3.4.3 Alarm Action

When an alarm condition exists the Model 220i will act in the following way:

1. The appropriate alarm output will be activated.

2. The display will flash the name of the alarm.

3. In some cases these alarms may be acknowledged from the front panel.

This will depend on whether they are programmed as continuous

or acknowledgeable alarms. This is set up during programming (see Section 4.1).

The differences between acknowledging continuous and acknowledgeable

alarms are described in table on the following page.

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Operation

Acknowledgeable Alarms

Continuous Alarms

1. These alarms are acknowledged by pressing the DISPLAY key.

1. A continuous alarm cannot be acknowledged.

2. Once the alarm is acknowledged the flashing on the LCD will cease, with the alarm message remaining solid. The message will remain on the screen until

the alarm condition no longer exists.

2. The flashing on the LCD cannot be stopped and will keep

flashing until the alarm condition no longer exists.

3. Once the alarm is acknowledged,the alarm output will be deactivated.

3. The alarms will only be deactivated when the level

(or contents) is outside alarm conditions.

Note that acknowledging the LL alarm will also acknowledge (and deactivate) the L alarm. Similarly, acknowledging the HH alarm will also acknowledge (and deactivate) the H alarm.

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Operation

3.4.4 Setting Alarms

To set any of the alarms:

1. Press the DISPLAY key until the name of the alarm to be changed appears (see Section 3.2.1).

2. Use the and keys to change the value of the alarm.

3. Press the DISPLAY key until the original level/contents screen appears.

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Operation

3.5 NON-LINEARITY

The Model 220i can be programmed to correct for the non-linearities in

irregular shaped tanks. These tanks have a non-linear relationship between the height of liquid and the volume of liquid.

A correction table, which corrects for non-linearities between the level signal

and the volume, can be programmed during setup. This table works as follows:

The user programs a normalised

(between 0 & 1) level (input)

signal.

The user programs the corresponding

corrected volume (output) point,which is also normalised.

The Model 220 performs a linear

interpolation between these points to obtain a profile of input signal versus corrected output for the volume of the tank.

Up to 25 points can be programmed this way.

The number of points

programmed is user determined and will depend on the shape

of the tank.

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Operation

DETERMINING THE NON-LINEAR CORRECTION TABLE

Data on tank non-linearity is usually supplied by the tank manufacturer, in the form of strapping tables. If this data is not available, the user will need to determine the relationship between level and volume. This can be done mathematically by equations, or experimentally, by conducting physical measurements.

In either case, the data must be normalised. An example of this is shown below:

Example.

A spherical tank has a diameter of 10m. The zero is at 0.5m and the span

is 10m. The following 15 point relationship has been determined

Input Volume

Normalised Inputs

for Table

Level (m)

Level T'mitter

Output

Input Output

0.5 4mA 3.796 0.000 0.000

1.094 17.421 0.0630 0.026

1.688 39.699 0.125 0.069

2.281 69.314 0.188 0.126

2.875 104.951 0.250 0.195

3.469 145.295 0.313 0.272

4.063 189.031 0.375 0.356

4.656 234.844 0.438 0.444

5.250 281.418 0.500 0.534

5.844 327.438 0.563 0.623

6.438 371.590 0.625 0.708

7.031 412.557 0.688 0.786

7.625 449.025 0.750 0.857

8.219 479.678 0.813 0.916

8.813 503.202 0.875 0.961

9.406 518.280 0.938 0.990

10.000 20mA 523.599 1.000 1.000

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Operation

Where,

So, for example, at 9.406m the normalised input is:

Similarly,

So, for example, at 9.406m the volume is 518.280m3 and the normalised output is:

Normalised Input =

Level

Level at 20mA

Level - (Level at Zero)

(Level at Span) - (Level at Zero)

If the Zero is > 0

Normalised Output =

Volume

Volume at 20mA

Volume - (Volume at Zero)

(V olume at Span) - (V olume at Zero)

If the Zero is > 0

(518.280 - 3.796) (523.599 - 3.796)

= 0.990

(9.406 - 0.5)

10 - 0.5

= 0.938

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Operation

SELECTING THE NUMBER OF POINTS FOR NON-LINEAR

CORRECTION

The user can program up to 25 points. However, the values at 4mA or

20mA which are set at 0 and 1 respectively, are not programmed. It is not always necessary to program all 25 points, as it will depend on the shape of the tank.

Tank Conversion Software

Tank Conversion Software 220CSW can be used to calculate theoretical

non-linearity correction tables for the most commonly used tank shapes (spherical,conical and cylindrical tanks).

The output from the program can be printed and is in a format suitable for

direct programming into the Model 220i. The program runs on a Windows 95 (or higher)operating system.

The software is only available from our website www.contrec.co.uk and can

be downloaded free of charge.

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Operation

3.6 FILTERING

Input fluctuations caused by tank agitation can interfere with the stability of the level and contents readings. For this reason, the Model 220i has a digital filter which will average out these fluctuations and enable accurate readings.

The degree of filtering of the input signal can be adjusted, depending on

the amount of fluctuation and the particular application. Values from 1 to 99 can be programmed, where 1 corresponds to no filtering and 99 corresponds to heavy filtering. Such flexibility in filtering means that highly accurate and stable readings can be obtained.

When programming the degree of filtering, it is advisable to start with no

filtering (the factor equals 1) and gradually increase until a steady reading is obtained. It is important that the filtering is not too heavy because this will cause an over damped response.

The following graph shows the time to reach 90% and 99% of a new reading

for a step change in input signal.

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Operation

Filter Factor vs Time to Reach New Reading

(for a step change in input signal)

100

120

0 10 20 30 40 50 60 70 80 90 100

Filter Factor

Time to Reach 90% and 99%

of New Reading (secs)

90% of Ne w Reading 99% of Ne w Rea din g

Page 28

Operation

3.7 DENSITY CORRECTION

In some cases, a pressure transmitter will be used to provide the 4-20mA signal to the Model 220i. In these cases, a density correction factor (KD) can be manually entered to compensate for those applications where the density of the fluid in the tank is likely to change. This would be the case if, initially, a particular fluid is stored in the tank and at a later stage a fluid of a different density is stored in the tank.

The density correction factor should initially be set to 1.000 when the Model

220i is calibrated for a given tank or vessel. If, at a later stage, a fluid of different density is stored in the tank, then it is only necessary to reprogram the density correction factor, rather than conducting a complete recalibration of the Model 220i.

The density correction factor is the ratio of the density of the fluid which

was originally in the tank, to the density of the new fluid.

This can be expressed as follows:

The density correction factor is then used to calculate level as:

Level = KD x Input Signal

where the input is normalised between 0% (4mA or 20mA if inverted) and 100% (20mA or 4mA).

The level is limited to 100% so that values of K

which result in a level

greater

than this will be displayed as 100%.

Density Correction Factor (K D) =

Density Value at Calibration

New DensityValue

Page 29

Operation

Example.

A tank is initially filled with toluene, which has a density at standard

conditions of 866 kg/m3. The Model 220i and a level transmitter are calibrated for the volume in this tank and the density correction factor (KD) is set to 1.000.

At a later date, the tank is filled with acetone, whose density at

standard conditions is 791 kg/m3.

The density correction factor is calculated as follows:

This value of KD is then programmed during setup (see Section 3.2.2).

866 791

= = .

Page 30

Programming

4. PROGRAMMING

The Model 220i is fully programmable with all parameters being stored

in memory.

To enter the Program Mode:

Remove the lower cover strip (the dark grey strip along the bottom of the front of the enclosure) and replace it the reverse side up. This brings a small magnet on the inside of the cover strip in contact with a reed switch inside the instrument. The word "Set" is then displayed.

To exit Program Mode:

The grey strip should be replaced the correct way up.

The key switch actions are as follows:

This key steps from digit to digit, causing the

digit to flash.

This key will increment a flashing digit or change

a parameter selection.

This key will step through the program sequence.

In stepping through the program sequence (using the DISPLAY key), the parameter description is displayed first, followed by the actual value or parameter. When a value or parameter can be changed it is shown as flashing.

DISPLAY

Page 31

Programming

4.1 PROGRAM STEPS

Step Display Description

SET

Level

Cont

Select whether alarms are assigned to level or contents.

Alarms are assigned to level. Alarms are assigned to contents.

TYPE

NE ND

Select whether alarms are normally energised or normally de-energised.

Normally energised. Normally de-energised.

ACT

N-AC

Select type of alarm action, either continuous on alarm condition or cancels when alarm is

acknowledged.

Continuous on alarm condition. Acknowledged and cancelled with display key.

DBAND

xx.xx

Alarm deadband.

Program alarm deadband as a % of maximum level or contents value.

FILT

1 to 99

The filter constant for filtering the input signal.

No filtering.

Very heavy filtering.

Page 32

Programming

Step Display Description

INPUT

N-INV INV

Select input type; either inverted or non-inverted.

Non-inverted (zero at 4mA). Inverted (zero at 20mA).

DISP

Dis

Select enable or disable. This will allow (enable) or not allow (disable) the user to

change the alarm setpoints and the density correction factor from the DISPLAY key.

Enable the changing of alarm setpoints and density correction factor.

Disable changing alarm setpoints and density correction factor.

UNIT

Cont

Vol

Select whether the word "Contents" or

"Volume" is displayed on the LCD.

"Contents" will be displayed.

The word "Volume" will be displayed in

preference to Contents. (Note there is no difference in operation if Volume is selected.)

C-DEC

The position of the decimal point for the contents. The user can select 0, 1, 2, or 3 decimal places.

C-SPAN

Span of the contents. The span can be programmed in the range of 0.000 to 9,999,999.

Page 33

Programming

Step Display Description

C-00

The zero of the contents. The zero can be programmed in the range of 0.000 to 9,999,999.

LIN

N-lin

Select whether the input signal is linear or

non-linear.

Linear.

Non-linear.

Steps 13-17 are displayed only if the input signal is non-linear.

No-PTS

The number of points for non-linear

correction.

The user can program up to 25 points. Note

the user does not program the values at 4mA

or 20mA, which are set at 0 and 1 respectively.

INP-01

Non-linear correction Input Point #01. The

input point for the first non-linear correction point is programmed in the range of 0.000 to

0.999.

Input points must be programmed in

ascending order.

OUT-01

The corresponding Output Point #01 for

non-linear correction is programmed in the range of 0.000 to 0.999.

INP-XXX

Non-linear correction Input Point #XX.

Subsequent input points are programmed in

the range of 0.000 to 0.999.

OUT-XXX

The corresponding Output Point #XX. The

corresponding output points are programmed.

SOFT

The software version used in the Model 220i is displayed.

Page 34

Signal Input

5. SIGNAL INPUT

The signal input is on terminals 3 and 4 and is connected as

follows:

Page 35

Alarm Outputs

6. ALARM OUTPUTS

Open collector outputs are provided for high and low level alarms. The output

can sink up to 200mA and can be used to power external relays, lights or audible alarms. The outputs are internally protected against voltage spikes.

Both outputs are separately isolated via opto-isolators.

Alarm Output Specifications

Maximum Current (sink): 200mA. Maximum Voltage: 30Vdc. Saturation V oltage: 0.8Vdc across outputs in energised state. Isolation: All outputs are separately isolated via

opto-isolators.

Page 36

Alarm Outputs

Connections

Page 37

Installation

7. INSTALLATION

7.1 WALL MOUNTING

A wall mounting bracket is supplied with each instrument. Round head

screws should be used to attach the bracket to the wall (countersunk screws

should not be used). The bracket is mountedfirst, with the tray section at

the bottom. The instrument is then mounted on the bracket with two screws as shown below.

LEVEL

100

VOLU

ALARM

Page 38

Installation

7.2 PANEL MOUNT VERSION

The panel mount version of the Model 220i is supplied with two panel

mount brackets and plug-in terminals, which are accessible from the rear of the instrument.

A diagram of the rear panel is shown below:

The cutout for this version is 141mm (5.55") wide x 87mm (3.43") high.

Page 39

Installation

7.3 REMOVING THE FRONT PANEL

The front panel should be removed as follows:

1. Remove the top and bottom cover strips (ie. the dark plastic strip) by levering a screwdriver under one end.

2. Undo the screws retaining the front. Do not remove the screws, they are retained by O-rings.

3. Remove the front panel from the housing.

To replace the front cover, follow the above procedure in reverse. Ensure that

the front panel is aligned at connector points before tightening the screws.

Page 40

Installation

LEVEL

100

VOLU

ALARM

LEVEL

100

VOLU

ALARM

Page 41

Installation

7.4 THE MAIN ELECTRONICS

The front section of the housing contains the microprocessor and display. It

is possible to adjust the display contrast via a small potentiometer on the board. The display contrast is shown below and this can be adjusted for optimum contrast.

Adjacent to this control is a reset switch, which can be used to reset

the microprocessor. Note that pressing this button will reset all setup parameters.

Display Contrast

RESET

CO NTR EC

SYST E MS

Page 42

Installation

7.5 WIRING

When connecting the Model 220i, it is good practice to use shielded cable.

The shield should be connected to earth at one end of the cable. The other

end of the shield should not be connected.

This wiring practice is mandatory in order to comply with the requirements

for Electromagnetic Compatibility as per EMC-Directive 2004/108/EC of the

Council of the European Community.

7.6 MAINTENANCE

All printed circuit boards must be repaired by Contrec Ltd. In the case of a

fault, no attempt should be made to repair the board as the intrinsically safe functionality may be impaired.

SPECIAL CONDITIONS FOR SAFE USE

To comply with this products ATEX/IECEx certification the special conditions

for safe use must be followed.

The Instrument type 220i shall be mounted in an area where electrostatic

charge/discharge will be avoided.

Page 43

Installation

7.7 TERMINAL DESIGNATIONS

4-20mA Input

3 4-20mA (-) 4 4-20mA (+)

Outputs

1 Low-low Alarm (-) 2 Low-low Alarm (+)

5 Low Alarm (-) 6 Low Alarm (+)

7 High Alarm (-) 8 High Alarm (+)

10 High-high Alarm (-) 11 High-high Alarm (+)

Page 44

Intrinsic Safety Connections

8. INTRINSIC SAFETY CONNECTIONS

When installing the Model 220i in hazardous areas, the wiring and

installation must comply with appropriate installation standards.

The approval uses entity parameters and an associated apparatus type

approval on the input/output connections to the 4-20mA current loop and alarms. The 4-20mA input and alarm outputs must, therefore, only be connected as shown on the following page to barriers with the specified parameters.

The Model 220i will connect directly to a 4-20mA current loop and

alarms, provided they do not exceed the following input parameters:

Ui = 28V Ii = 93mA Pi = 653mW

The internal capacitance seen on the input (terminals 3-4) is 0.02uF while

the internal capacitance seen on the output (terminals 1-2, 5-6, 7-8 and 10-11) is 0.1uF maximum. Inductance is negligibly small on both the input and output.

Outputs

The four open collector outputs must only be connected to certified

IS equipment via barriers as shown on the following page. Only certified intrinsically safe solenoids may be used for IS applications.

Page 45

Intrinsic Safety Connections

MODEL 220

LEVEL MONITOR

2(+)

1(-)

6(+)

5(-)

4(+)

3(-)

APPROVED

4-20mA

CURRENT

LOOP

TRANSMITTER

IS Barrier 1

Ro = 300 ohm

IS BARRIERS 1-5

Uo = 28 V maximum

Io = 93 mA maximum

Po = 653 mW maximum

L/R < specified for selected barrier

SAFE AREA HAZARDOUS AREA

Cable Length < 5 km

Intrinsically Safe Installation

IS Barrier 2

Ro = 300 ohm

IS Barrier 3

Ro = 300 ohm

SAFE AREA

Approved

IS Coil

Approved

IS Coil

Uo = 28 V maximum

Io = 93 mA maximum

Po = 653 mW maximu

8(+)

7(-)

IS Barrier 4

Ro = 300 ohm

Approved

IS Coil

11(+)

10(-)

IS Barrier 5

Ro = 300 ohm

Approved

IS Coil

Page 46

Index

4½ Resolution, 7

Alarms, 13 Acknowledgeable

Alarms, 15 Alarm Deadband, 15 Alarm Outputs, 30

Calculation of

Contents, 7 Contents, 7 Continuous, 15

Density Correction

Factor, 24

Electronics, 36

Filtering

Filter Factor, 22

Front Panel Operation, 8

Hazardous, 3 High Alarms, 14

Installation, 32 Intrinsic Safety, 3, 44

Level Bar Graph, 6 Low Alarms, 14

Microprocessor, 36 Model Number, 2

Non-Linearity, 18 Normalised, 19

Open Collector

Outputs, 30

Panel Mount, 33 Programming, 25

Relay & Power

Module, 39

Signal Input, 29 Span

Offset, 7

Standards, 1

Tank Conversion

Software, 21

Terminal

Designations,

38 Test Mode, 12 Timeout, 12

Wall Mounting, 32 Wiring, 37