Safety Interlock Switches
MA Series
Magnetically Actuated
Safety Interlock Switches
• Large selection—choose from a large selection of contact configurations
housed in plastic to satisfy most application requirements
• NEMA 6 enclosure enables the MA Series switches to satisfy most
application requirements (MA 3, 4, 5 are NEMA 4)
• Misalignment tolerant—the non-contact actuation of the switches makes
them very tolerant to misalignment of up to 10 mm (0.39 in.)
• Variety of terminations—select various cable lengths or terminal strip
termination for easy installation. Cable connector on selected models.
• Long life—the MA Series is designed for a minimum of one million actuations
• A Rapid Delivery Product: Select models are available for shipment today or within 3 to 5 days
R
C
US
Specifications
Electrical
Safety Contacts:
Safety Contact Operating Distance:
Auxiliary Contacts:
All Models Unless Indicated
AC models
DC models
Conforms to EN1088, EN292, EN60204-1
UL and C-UL listed
MA-2, 4, 12, 13, 14, 15, 16, 21
MA-3
Aux. Contact Operating Distance:
MA-2, 4, 16, 21
MA-3
Safety Rated Voltage:
AC models: All except MA-10
AC models: MA-10
DC models
Safety Rated Current:
AC models: All except MA-3
AC model: MA-3
DC models: All except MA-15
DC model: MA-15
Internal Fuse:
AC models
DC models
External Fuse (Customer Supplied): AC models
DC models: All except MA-15
Electrical Life:
Mechanical—Special Safety Reed
Closing Time:
Drop-Out Time:
Bounce Time:
Shock:
Vibration:
Mechanical
Mounting:
Any position
Case & Actuator Material:
Molded ABS
Wiring Connection:
Various lengths or male M12 micro connector
Weight:
Approx. 384 g (14 oz.)
Color:
Red
Mechanical Life:
10 x 10
6
Environmental
Protection:
All models except MA-3, 4, 5
IP67 (NEMA 6)
MA-3, 4, 5
IP65 (NEMA 4)
Operating Temperature:
All models except MA-3, 4, 5
-10 to 55°C (14 to 131°F)
MA-3, 4, 5
-10 to 65°C (14 to 149°F)
Compliance
Standards:
EN1088, EN292, EN60204-1
Approvals/Listings:
CE marked for all applicable directives
All models: except MA-3, 4, 5
UL and C-UL
MA-3, 4, 5
cCSAus
Specifications are subject to change without notice. Note: The safety contacts of the STI switches are described as normally closed (N/C) i.e., with the
guard closed, actuator in place, and the machine able to be started.
MA-1 thru 5, 10, 12, 13, 16 — 1 N/C
MA-13, 16, 21 — 2 N/C
MA-12, 13, 14, 16 — 1 N/C
MA-13, 15, 16, 20, 21 — 2 N/C
Make 7-12 mm (0.28-0.47in.); Break 12-25 mm (0.47-0.98 in.)
1 N/O
1 N/C
Make 8-13 mm (0.39-0.51 in.); Break 8-10 mm (0.31-0.39 in.)
Make 21 mm (0.83 in.); Break 24 mm (0.94 in.)
230 VAC
110 VAC
30 VDC
2 A, fuse externally 1.6 A quick acting
3 A, fuse externally 2.5 A quick acting
1 A, fuse externally 800 mA quick acting
0.3 A max., fuse externally 0.2 A quick acting
2 A fast acting
1 A fast acting
1.6 A fast acting
0.8 A fast acting
1 x 10
6
Safety
Aux.
3.0 mS
0.5 mS
2.1 mS
0.3 mS
0.7 mS
0.7 mS
10 G
10 G
10 G, 50 to 100 Hz
G
www.sti.com/info
G-97
MA Series
Safety Interlock Switches
Basic Body Styles
MA-1, MA-2, MA-20 and MA-21
MA-10 and MA-16
MA-12 and MA-13
MA-14 and MA-15
G
MA-3, MA-4 and
Door Closed, Machine RUN
MA-5
2mm
SLIDING DOOR
Operation
Operating Principle
Mounting Examples
2mm
Switch
Actuator
2mm
Door Closed, Machine RUN
Door
2mm
Closed, Machine RUN
SLIDING DOOR
Contact Arrangement
Min 50mm
2mm
2mm
SLIDING DOOR
Switch
Switch
Actuator
MA-1, 5, 10, 11,
12, 13, 14, 16
Door 1
Actuator
Door 1
Min 50mm
Door
2
Door 2
Switch
MA-2, 4, 11, 12, 13, 14, 16
Min 50mm
Actuator
Switch
Switch
Actuator
Door 2
Encapsulated in the MA Series
is a unique high-power industrial
reed which is de-rated by a
non-resetable overload protection
circuit depending on switch type.
On presenting the actuator to the
switch, the high intensity magnetic
field from the actuator causes the
contacts to close. On removing the
actuator (opening the door), the
safety contacts open, isolating the
machine.
Actuator
Door 1
MA-3, 11, 13, 16, 20
It is advisable, where possible, to
mount the switch and actuator on
non-ferrous materials otherwise it
may affect the operating distances.
MA-11, 13, 15, 16, 21
Door Closed, Machine RUN
Door Closed, Machine RUN
Door Open, Machine STOP, Door Covering Switch
No access to switch
No access to
thus preventing attempts
switch
thus preventing
to defeat the interlock
attempts
to defeat the interlock
Door Open, Machine STOP, Door Covering Switch
2mm
SLIDING DOOR
2mm
SLIDING DOOR
SLIDING DOOR
SLIDING DOOR
Wherever possible the units should be mounted so that no access can be obtained to the switch when
Door Closed, Machine RUN
Door Open,
the guard door is open, thus preventing attempts to defeat the safety system.
Machine STOP, Door Covering Switch
2mm
SLIDING
Select models are available for Rapid Delivery.
DOOR
No access to switch
thus preventing attempts
to defeat the interlock
SLIDING DOOR
Visit this product on www.sti.com for details..
G-98
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MA Series
Safety Interlock Switches
Applications
Typical Application of MA Series with a Safety Monitoring Relay
Typical applications are on
sliding guard doors or swing-
ing guard doors.
24 VAC/DC, 110 VAC
K1
(AUX)
START
MOMENTARY
PUSH
BUTTON
K2
(AUX)
L1 L2 L3
L1 L2 L3
STOP
MOMENTARY
PUSH
BUTTON
A1
Power supply
(S11 = 24 V)
S11
S21
Relay control and
fault monitoring
13
23
GUARD
CLOSED
BLUE
FUSE
MA SERIES
INTERLOCK
SWITCH
+
K2
K1
+
CONTACT PROTECTION e.g. THERMAL CUT OUT
K1
K2
CONTACT PROTECTION e.g. THERMAL CUT OUT
BROWN
SR101A
A2
14
24
EB SERIES
LATCHING
E-STOP
BUTTON
FUSE
K1
FUSE
K2
M
M
G
full explanation
and fault detection,
✎
For a“Common Circuit of the circuitinoperating principleSection of this catalog on page A-31
see
Examples” the Expert Area
Pin Assignments with Connector Option
6-pin Micro AC 1/2”-20
3
2
1
4
6
5
1
5
Safety N.C.
Safety N.C.
6
2
1
2
6
3
5
4
MA 21 QD
4
3
Aux N.O.
2
1
3
1
4
3
2
1
4
3
MA 16 QD
MA 2 QD
4-pin Micro DC M12
2
MA 2, 16, 20 QD
Safety N.C.
1
3
2
3
1
4
MA 20 QD
Aux
MA 2 QD N.O.
MA 20 QD N.C.
4
Select models are available for Rapid Delivery.
Visit this product on www.sti.com for details..
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G-99
PCB Design
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