Rockwell Automation 440C Guardmaster 440C-CR30 Configurable Safety Relay User Manual - Manual (Page 35)

Rockwell Automation Publication 440C-UM001C-EN-P - November 2014 35
Chapter
5
Pulse Testing
The CR30 performs three types of pulse testing functions:
• N.O. inputs
• N.C. inputs
• Outputs
Normally Open Input Pulse
Testing When a safety input is configured for normally open (N.O.) operation, the CR30
periodically checks the status of the input. The purpose of the test pulse is to
detect short circuits in the wiring to 24V DC, 0V and between two channels.
This test is independent of the “Input Test Pulses”. Six terminals (12…17) can be
configured for normally open operation.
When a terminal is configured for N.O. operation, the CR30 tests the status of
each terminal by generating a test pulse as shown in
Figure 17 .
The normally open input pulse testing cannot be configured to be on or off. If the
terminal is configured to be N.O., the pulse testing is performed by the CR30.
Figure 17 - N.O. Terminal Test Pulse
When multiple terminals are configured for normally open operation, the CR30
tests each one at 500 ms intervals. This test sequence is repeated every 6.4
seconds.
In Figure 18 on page 36 , terminals 12, 14, 15, and 17 are configured for N.O.
operation, and are tested. Terminals 13 and 16 are configured for normally closed
(N.C.) operation, therefore the test pulse does not occur on these two terminals.
24V
0V
0 640μs