Functions
Leuze electronic GmbH + Co. KG
MSI-SR4B
10
4
Functions
Single-channel E-Stop circuit, manual start
see figure 7.3
After applying the supply voltage to A1 and A2 and with the E-Stop button not actuated, relays K1 and K2
of the MSI-SR4B pick up upon actuation of the start button and lock. The release circuits 13-14, 23-24 and
33-34 close, signal circuit 41-42 opens. Upon actuation of the E-Stop button, K1 and K2 go dead and drop
out. The release circuits open, the signal circuit closes. With one-channel E-Stop wiring, up to category 2
acc. to EN ISO 13849-1:2015 is achieved. Earth faults in the button circuit are detected.
Two-channel E-Stop circuit, manual start
see figure 7.1
Function/operating principle as described above. In addition, contactor contacts K3, K4 are looped into the
start circuit (reset) (EDM).
With two-channel E-Stop wiring, up to category 4 acc. to EN ISO 13849-1:2015 is achieved.
Downstream safety circuit for optoelectronic protective devices type 4, IEC 61496-1:2020
see figure 7.1, see figure 7.2
Optionally, light beam safety devices of type 4 can be connected with relay outputs or with fail-safe semi
-
conductor outputs. When calculating the safety distance, the regression delay of the MSI-SR4B of 10 ms
must be included. As an alternative to the manual start, a bridge can be placed between S34 and S35 for
automatic start. With this operating mode, it must not be possible to reach or step behind the protective
sensor.
Two-channel sliding safety guard monitoring
see figure 7.3
Based on the specified signal sequence, when using two, forced position switches, the direction-depen
-
dent actuation of the contacts, e.g. of a safety guard, is monitored. For automatic start (bridge S34 - S35),
reaching or stepping behind must not be possible.
Signal sequence monitoring
The function expects the first signal at S22 and the second signal at S12. The time offset is arbitrary. If,
due to, e.g., misalignment of a contact actuator, the times of the signals are swapped, this is tolerated up
to max. 20 ms. Afterwards, the release circuits of the MSI-SR4B close. Signal sequence monitoring is only
active if automatic start is used.
Monitoring of the sensor inputs
In the event of a cross circuit at inputs S12 and S22 or a short to ground at input S12, output relays K1 and
K2 of the MSI-SR4B are switched off via an electronic fuse. The MSI-SR4B is again ready for operation
approx. 2 s after the cause of the malfunction has been eliminated.
Start button monitoring during manual start
To detect static faults or blocking of the start button, the button function is monitored for signal changes.
Enabling occurs when the button is released (1/0 signal change). This function is deactivated during auto
-
matic start.
Contactor monitoring (EDM) with manual start
see figure 7.1
For function monitoring of the external contactors, their NC contacts are looped into start circuit S35 with
start button in series.
Contactor monitoring (EDM) with automatic start
For function monitoring of the external contactors, their NC contacts are looped in between S34 and S35
in series.
