a104_02-User's Guide general.pdf

ELECTRIC ACTUATORS

A104/02

USERÓS

GUIDE

SUMMARY

CHOOSING

THE RANGE

Analysis

Environment

Operation type

Fail safe

p10

Choosing the range

p12

Mechanical and electrical features

CHOOSING

THE

CONTROL

p16

The possibilities

p17

Comparison

p18

Integral control

p20

Signalling options

FIELDBUS

p21

Communication by fieldbus

USERÓS

GUIDE

LE SERVOMOTEUR

ELECTRIQUE

The electric actuator, initially designed to operate

valves and dampers has now become a mainte-

nance and control tool.

the control boxes to the electric actuator or to

remotely install them into control cabinets. A series

of controls are proposed to the users on all ranges.

The integral version, adapted or not to modulation

provide for local or remote controls. The smart ver-

sions combine the advantages of the classic inte-

gral versions with the flexibility offered by the

microprocessor : maintenance, automatic adjust-

ment, etc.

The integration of the control elements directly insi-

de the actuator provides for a command perfectly

adapted to the various functions of the device.

The data of its internal sensors are conveyed by a

fieldbus, informing the users of the valve operating

conditions and enabling remote modification of

some parameters.

The user can thus modify the operating parameters

locally and without opening the covers, providing

for a real Ðplug and playÑ.

Communication by fieldbus is possible whate-

ver the range or control selected.

As the fieldbus is now available on a growing num-

ber of facilities, large volumes of data can be trans-

ferred while considerably reducing the on-site

wiring costs. Several Bus interfaces are available

whatever the electric actuator and its control.

Ranges suited to the need

Depending on the element to be driven, the electric

actuator shall be designed so as to meet the requi-

rements of its operating environment. Data such as

the degree of water tightness, the desired explo-

sion-proof protection and also the presence of cer-

tain corrosive agents must be perfectly known by

the user and taken into account.

Thus, the choice of an electric actuator is critical as

regards the reliability of the industrial process but

also the optimum operation at commissioning as

well as throughout the device lifetime.

The L. BERNARD products have been designed to

be tailored to the required needs with the best qua-

lity/cost combination. They are manufactured

according to recognized quality standards :

Requirements can be of several types : for instan-

ce, electrical actuators intended for nuclear plants

shall feature high resistance to earthquakes or

extreme temperatures.

Operating conditions are a key factor and the desi-

gn itself depends on requirements such as the type

of operation : on/off or modulating, the number of

operations (3000 or 1 million) or the precision of

positioning (low or high). With the L. BERNARD

classification, users can easily define their needs.

Moreover, a fail-safe system is available for the

users, even with an electric actuator.

As the L. BERNARD products are constantly

enhanced, please check the specifications when

placing your orders.

Choice of control depends on process

During installation, users can choose to integrate

USERÓS

GUIDE

CHOOSING

THE RANGE

Analysis

Four questions to be asked for determining

the most suited range :

1. TYPE OF MOVEMENT OF THE DEVICE TO BE DRIVEN

Type of device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Movement

Butterfly valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Quarter-turn

Ball and Plug valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Quarter-turn

Dampers and louvers . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Quarter-turn

Globe valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Multiturn

Pinch and diaphragm valves . . . . . . . . . . . . . . . . . . . . . . . .

Multiturn

Gate or knife valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Linear

2. TYPE OF ENVIRONMENT

Site of installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Actuator enclosure protection

Normal environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Watertight

Hazardous areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Explosion proof

Nuclear sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nuclear

Corrosive atmosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Special

USERÓS

GUIDE

CHOOSING

THE RANGE

Analysis

3. TYPE OF OPERATION OF THE DEVICE TO BE DRIVEN

Type of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Actuator function

Open or close the full stroke, . . . . . . . . . . . . . . . . . . . . . . . .

On-Off

on average 20 to 30 times/day.

Select intermediate positions,

Modulating

with good precision (better than 2 %) . . . . . . . . . . . . . . . . .

Class III

on average 360 times/day.

Select intermediate positions,

Modulating

with high precision (better than 1 %) . . . . . . . . . . . . . . . . . .

Class II

on a permanent basis every 2 or 3 seconds.

Fast positioning

Modulating

with an excellent precision (0,5 % or better) . . . . . . . . . . . .

Class I

and continuous movement.

4. SAFETY POSITION

Safety requirement . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type of actuator

In case of power supply failure,

the valve can remain in the last position . . . . . . . . . . . . . . .

Stay put

without any danger.

In case of control signal failure,

Actuator with automatic

the valve should move automatically . . . . . . . . . . . . . . . . . .

emergency action

to the safe position.

In case of a complete power failure,

the valve should move automatically . . . . . . . . . . . . . . . . . .

Fail safe

to the safety position.

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