SG-BWS-T4
19
4.7.
Connecting the external relays and EDM
To use the EDM function available in the BW-ST4, simply connect devices as shown below.
24VDC
K1
K2
Power
Safe
Break
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
5| 6| 7| 8
1| 2| 3| 4
0VDC
NC
NC
EDM
Fig. 17 EDM connections
External devices monitoring (EDM) checks whether the relays (or other control devices) have really
opened the power circuit due to a dangerous condition detected by the safety sensors. This function
monitors normally closed contacts upon OSSD status change.
EDM function is enabled, terminal 3 is left disconnected
(see 4.3 “Complete list of connections”).
Activation is confirmed by the decimal point (dot) being displayed on control unit screen.
If EDM
is not used, it will be necessary to leave terminal 4 disconnected
or consider 0VDC (see
4.3).
T
C
350 msec: time after SAFCN OFF-ON switch when EDM test is performed.
T
0
100 msec: time after SAFCN ON-OFF switch when EDM test is performed.
Fig. 18 EDM Timings
To exploit the EDM function available in the SG-BWS-T4 system, you simply have to connect in series
the two NC contacts of the external relays, then connect the free ends respectively to 24V and contact
4 of control unit, as shown in the above diagram.
OSSDs STATE
NORMAL
SAFE
