MSR8T Datasheet, PDF (1/1 Pages) Allen-Bradley – Monitoring Safety Relays

Safeguarding Applications
Non Contact Interlocks
Ferrogard 6, Bulletin 800, MSR8T, Bulletin 100S, Single Channel
24V AC/DC, 110V AC, 230V AC
Start
Momentary
Push Button
K1 (Aux)
K2 (Aux)
L1 L2 L3
L1 L2 L3
L1 L2 L3
Stop
Momentary
Push Button
K3 (Aux)
Fuses
Fuse
K1
Guard
Closed
Blue
Brown
Ferrogard
FRS6
Interlock
Switch
A1 S13 13 23 33 43 51 X1
Minotaur
MSR8T
A2 S14 14 24 34 44 52 X2
K2
K3
Bulletin 800
Latching
E-Stop
Auxiliary Circuit
(Alarm or Indication)
Fuses
MMM
K1
K2
K3
Bulletin 100S
or 700S
Circuit Status
Circuit shown with guard door closed and ready for motor starting.
Operating Principle
This is a single channel system with monitoring of the contactors. It uses a Minotaur MSR8T monitored safety relay to distribute the signal
from the interlock and E-Stop switches to three contactors.
Opening the guard or operating the E-Stop device will open the input circuits (S13-S14) to the Minotaur MSR8T. The output circuits
(13-14, 23-24 & 33-34) will cause the contactors to isolate to power to the respective motors.
Fault Behaviour and Detection
The integrity of the circuit depends on the suitability of the components (conformity with standards, tried and tested principles, etc.) and the
nature of the wiring installation (use of protective conduit, short wiring runs, no movement of wiring, etc.).
The Minotaur MSR8T provides an ensured switching action. Contactor monitoring is provided via terminals X1-X2. When more than one
contactor is used, if one of the contactors sticks ON, the restarting of the other two will be prevented by the Minotaur.
The MSR8T can be configured with two contactors in series to control one motor and if either contactor sticks ON, the motor will stop on
command due to the other contactor but the MSR8T will not reset.
Safety critical single faults within the Minotaur MSR8T itself will be detected. It does not detect some faults at its input circuit and therefore it
is possible for a single fault to cause a loss of safety function.
Comments
This type of system is widely used where an intermediate relay is required between the Interlock switch or E-Stop device and the contactor(s).
An ordinary relay would not be suitable for this purpose because of its failure modes. This is typically the case where multiple motors are being
switched or a higher current switching capacity is required. It is suitable in applications that have low to medium risk and where the wiring can
be properly protected.
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