User manual

LD Language Elements

SR2MAN01 11/2007

Use as a Coil To use an auxiliary relay as a coil, 4 modes are available:

z Contactor mode,

z Impulse relay mode,

z Latch mode,

z Unlatch mode.

Contactor mode:

Symbol of an auxiliary relay, used as a coil in contactor mode:

The relay is energized if the contacts to which it is connected are conducting.

Otherwise it is not energized.

Impulse relay mode:

Symbol of an auxiliary relay, used as a coil in impulse relay mode:

Pulse energization, the coil changes state on each pulse it receives.

Latch mode:

Symbol of an auxiliary relay, used as a coil in latch mode:

The SET relay, also called the latch relay, is energized as soon as the contacts to

which it is connected are conducting, then stays set even if later the contacts are no

longer conducting.

This behavior is identical to that of an RS logic flip-flop.

Unlatch mode:

Symbol of an auxiliary relay, used as a coil in latch mode:

The RESET relay, also called the unlatch relay, is deactivated when the contacts to

which it is connected are conducting. It remains deactivated even if later the

contacts are no longer conducting.

Note: for reasons of increasing compatibility for programs operating with Zelio 1,

the four types of mode for any given Q output coil or M auxiliary relay can be used

in the same wiring diagram in Zelio 2.

[ M-

M-

SM-

RM-