Banner Extension Modules - Manual (Page 5)

Extension Module –
Model EM-T-7A
page 5
Banner Engineering Corp. • Minneapolis, U.S.A.
Website: http://www.baneng.com • Tel: 888.373.6767
WARNING . . .
Use of Arc Suppressors
If arc suppressors are used,
they MUST be installed as shown across
the actuator coil of the master stop
control elements (MSC1 to MSC4).
NEVER install suppressors directly
across the output contacts of the
Extension Module. It is possible for
suppressors to fail as a short circuit. If
installed directly across the output
contacts of the Extension Module, a
short-circuited suppressor will create an
unsafe condition which could result in
serious injury or death.
!
WARNING . . .
Maintain Control Reliability
NEVER wire an intermediate
device (e.g., a programmable logic
controller/ PLC), other than a safety
relay, between any safety output of the
Extension Module and the master stop
control element it switches. To do so
sacrifices the control reliability of the
control-to-machine interface, and creates
an unsafe condition which could result in
serious injury or death. Whenever a
safety relay is added as an intermediate
switching device, a normally-closed
forced-guided monitor contact of that
relay must be added to the series
feedback loop.
(Reference ANSI B11.1 – 1988,
Appendix B4)
!
23 33 43
14 24 34 44
EM-T-7A
+24
V dc
0
V dc
L1
L2
13
A2
Machine Control Circuit
Primary
Safety
Device
Monitoring Contact
Feedback Input
Monitoring Contact
Feedback Input A1 K Y1
MSC1
MSC Monitor Contacts
MSC2 MSC3 MSC4 MSC1 *
MSC2 *
MSC3 *
MSC4 *
Machine
Master Stop
Control Elements
*Arc Suppressors
(See Warning)
U Y2
Figure 3. Generalized EM-T-7A Hookup for One-Channel Control
NOTE:
This hookup is general in
nature. Your specific hookup
may vary significantly,
depending on the Primary
Safety Device used and the
machine control configuration.
One-Channel Control (Figure 3)
One-channel control affords simplicity of wiring. However, one-channel wiring requires
eliminating the possibility of an unsafe failure of the control wires (which connect the
output of the Primary Safety Device to the input of the Extension Module). One of the
ways to reduce the probability of such failure is to locate the Primary Safety Device
adjacent to the Extension Module in the same enclosure.
The output of the Primary Safety Device must consist of two or more series-connected,
normally open contacts, coming from forced-guided safety relays. These contacts
must be monitored for failure by the Primary Safety Device. In addition, a single contact
failure cannot prevent normal stopping action, and a successive cycle cannot be
initiated until the failure has been corrected. An example of this type of output is any
single output channel of a Banner E-stop safety module.