Rockwell Automation 440C Guardmaster 440C-CR30 Configurable Safety Relay User Manual - Manual (Page 36)

36 Rockwell Automation Publication 440C-UM001C-EN-P - November 2014
Chapter 5 Pulse Testing
Figure 18 - Test Sequence
Normally Closed Input Pulse
Testing Terminals 12…17 can be configured to generate test pulse outputs. These signals
are used to test for short circuits in the wiring to 24V DC, 0V and between two
channels that are wired to separate test pulse sources (one channel that is sourced
from an odd number terminal [13, 15, and 17], and the other one from an even
number terminal [12, 14, and 16]).
The CR30 generates three distinct pulses, called A, B, and C. Each pulse is 1.7 ms
wide. Pulse Test B immediately follows Pulse Test A. Pulse Test C immediately
follows Pulse Test B. The pulse tests are repeated every 25 ms.
The timing diagram in Figure 19 shows an example of the pulse testing when the
respective terminals are configured for A, B, and C.
Figure 19 - Timing Diagram
Terminal 12
Terminal 13
HI
LO
HI
LO
Terminal 14
Terminal 15
HI
LO
HI
LO
Terminal 16
Terminal 17
HI
LO
HI
LO
1 4 3 2 5 6
500ms intervals
IMPORTANT Safety systems requiring a Category 4 structure per ISO13849-1 and SIL 3
rating per IEC61508 must use pulse testing for the dual channel N.C. contacts.
Pulse testing for Category 3, 2, and 1 structures and SIL 2 and 1 ratings is
recommended.
Terminal 13 - B
Terminal 14 - C
Terminal 12 - A
24V
25ms
1.7ms
0
0V
24V
0V
24V
0V
Terminal 16 - B
Terminal 17 - C
Terminal 15 - A
24V
0V
24V
0V
24V
0V