ABB C576, C577 Application Information

Electronic

7

Safety relays

Application examples

C576, C577

Application

The safety relay C 576 can be used in safety circuits as per
VDE 0113 Part 1 (11.98) or EN 60 204-1 (11.98), e.g. with movable covers and
safety gates; the safety relay C 577 in EMERGENCY STOP circuits as per EN

418. Depending on external connections, category 4 as per DIN EN 954-1 is
achievable.

Functions and connections

The safety relays C 576/C 577 have two release circuits (safety outputs) confi gured
as NO contacts. The number of release circuits can be increased by adding one or
more C 579 extension units.
Three LEDs indicate operating state and function.
When the EMERGENCY STOP button or the limit switch is unlocked
and when the ON button is pressed, the internal circuit of the safety relay and the
external contactors are checked for proper functioning.
On the C 577, the ON circuit Y33, 34 is checked for short circuit.

7

This means that a fault is detected when Y33, 34 is closed before
the EMERGENCY STOP button is closed.
The EMERGENCY STOP button or the limit switch are connected to terminals Y11,
12, 21, 22. The ON button is connected in series to the NC contacts of the external
contactors (feedback loop) to terminals Y33, 34.

Terminal marking

Supply voltage A1 L/+
A2 N/-

Sensors Y11, 12 Channel 1 EMERGENCY
STOP
or limit switch
Y21, 22 Channel 2 EMERGENCY
STOP
or limit switch
Y33, 34 ON button, feedback loop
Outputs 13, 14 Safety output 1 (n/o contact)
23, 24 Safety output 2 (n/o contact)

Fault clearance

1. Switch supply voltage off.

2. Clear fault or replace device.

3. Switch supply voltage back on.

Cable length

for 2 x 1.5mm
150nF/km sensors and power supply lines)

Internal circuit

2

max. 1000m total cable length for

Y21 Y33

Y11

A1

ϑ

1

2

13 23

4

3

5

Operation

LEDs Operation

POWER Channel 1 Channel 2 PS E-Stop ON Safety outputs

ON non activated closed

activated
activated non open

activated

non non open

activated activated

Faults

Relay fusion-welded open

Motor cont. fusion-welded

Defect in electronic

Short circuit in ON circuit

Cross or ground faults in
EMERGENCY STOP circuit
(min. fault current
I

C 577 with monitored start for EMERGENCY STOP

Category 4 acc. to EN 954-1

24 V AC/DC

open closed

N/ñ

C 577 with monitored start for EMERGENCY STOP

Category 4 acc. to EN 954-1

24 V AC/DC

EMERGENCY-STOP

N/ñ

= 0.5A; PTC fuse trips)

Kmin

Y12Y11

Y33 Y34

C576

A2

Y22Y21

K1

K2

A1 Y12Y11

C577

Y21Y22 A2

L/+

13 23A1

K1

K2

M

14 24

N/ñ

L/+

ON

Y34Y33

13 23

K1

K2

14 24

M

K2

K1

N/ñ

Y22 Y34

Y12

A2

14 24

7.46 Low Voltage Products & Systems

AC 1000 - 11/03