Rockwell Automation Allen-Bradley Guardmaster 440R-S35011, User Manual

Page: 23 / 50

Rockwell Automation Publication 440R-UM014D-EN-P - December 2019 23
Chapter
5
Timing Diagram
Timing Diagram Procedure
A typical timing diagram of MSR55P safety relays is shown in Figure 14 on
page 24 .
1. Upon power-up, the MSR55P safety relay performs internal safety
checks.
2. With the motor at standstill, the outputs are energized.
3. When the motor is turned ON, the outputs are de-energized.
4. A motor stop command is issued, and the motor spins down.
5. The back EMF reaches the level of the V
m
setting, the standstill delay
timer starts. The position of the t
s
potentiometer determines the
duration of the delay.
6. When the timing cycle completes, standstill is considered achieved and
the outputs are energized.
7. If one of the monitoring voltage signal lines break, the outputs are
de-energized and the semiconductor ERR output turns ON after 2.5
seconds.
8. If the line is reconnected, no changes are noticed if the manual fault reset
is used.
9. When the fault reset is closed, the outputs are energized.
10. The motor is turned back on, and the safety outputs are de-energized.
11. When voltage-free contacts control the motor, the MSR55P safety relay
can detect line breakage on L2 and L3. After a 2.5 second delay, the
semiconductor ERR signal turns ON. The ERR signal must be used to
initiate a stop command to the motor. The outputs remain de-energized.
12. The line break is reinstated.
13. Upon closure of the reset signal, the outputs are energized.
IMPORTANT The MSR55P safety relay does not detect line breakage with motor
running and connected to an electronic drive.