Precautions for All Relays with Forcibly Guided Contacts

Note: Refer to the Safety Precautions section for each Switch for specific precautions applicable to each Switch.

■ Precautions for Safe Use

Mounting

The Relays with Forcibly Guided Contacts can be mounted in any

direction.

Relays with Forcibly Guided Contacts

While the Relay with Forcibly Guided Contacts has the previously

described forcibly guided contact structure, it is basically the same as

an ordinary relay in other respects. Rather than serving to prevent

malfunctions, the forcibly guided contact structure enables another

circuit to detect the condition following a contact weld or other

malfunction. Accordingly, when a contact weld occurs in a Relay with

Forcibly Guided Contacts, depending on the circuit configuration, the

power may not be interrupted, leaving the Relay in a potentially

dangerous condition (as shown in Fig. 1.)

To configure the power control circuit to interrupt the power when a

contact weld or other malfunction occurs, and to prevent restarting

until the problem has been eliminated, add another Relay with

Forcibly Guided Contacts or similar Relay in combination to provide

redundancy and a self-monitoring function to the circuit (as shown in

Fig. 2). Refer to the Technical Guide section.

The G9S/G9SA/G9SB Safety Relay Unit, which combines Relays

such as the Relay with Forcibly Guided Contacts in order to provide

the above-described functions, is available for this purpose. By

connecting a contactor with appropriate input and output to the

Safety Relay Unit, the circuit can be equipped with redundancy and a

self-monitoring function.

CE Marking

(Source: Guidelines on the Application of Council Directive 73/23/

EEC)

The G7SA, G7S and G7S-

@-E have been recognized by the VDE for

meeting the Low Voltage Directive according to EN requirements for

relays and relays with forcibly guided contacts. The Low Voltage

Directive, however, contains no clauses that specify handling

methods for components, and interpretations vary among test sites

and manufacturers. To solve this problem, the European Commission

has created guidelines for the application of the Low Voltage

Directive in EU. These guidelines present concepts for applying the

Low Voltage Directive to components. The G7SA, G7S and G7S-

@-

E, however, do not display the CE Marking according to the concepts

in the guidelines.

VDE recognition, however, has been obtained, so there should be no

problems in obtaining the CE Marking for machines that use the

G7SA, G7S or G7S-

@-E. Use the manufacturer’s compliance

declaration to prove standard conformance.

Contents of the Guidelines

The Guidelines on the Application of Council Directive 73/23/EEC

apply to components. Relays with PWB terminals are not covered by

the Low Voltage Directive.

K1

S1

S2

K1

K1

S1

11

12

21

22

S2

K1

K2

K3

+

−

D

F1

K3 K1

K1

K1

K3 K2

K2

K2

K3

A1 A2 T11 T12

Y1 X1

13

B1

PE T21

T22

14

Fig 1

Fig 2

Power source

Power source

http://www.ia.omron.com/

C-1

(c)Copyright OMRON Corporation 2007 All Rights Reserved.