Rockwell Automation 21G PowerFlex 750-Series AC Drives Reference Manual User Manual
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Rockwell Automation Publication 750-RM001F-EN-P - February 2012
Chapter 4
Speed Monitoring I/O Signals
Figure 4 - Cycle Inputs Required
If inputs are configured with the following dual channel settings, an Input fault
occurs if the inputs are discrepant for longer than 3 seconds or if a ‘cycle inputs
required’ condition exists for longer than 3 seconds.
• 2 = Dual-channel equivalent 3 s (2NC 3s)
• 4 = Dual-channel complementary 3 s (1NC + 1NO 3s)
• 5 = Dual-channel SS equivalent 3 s (2 OSSD 3s)
If inputs are configured with one of the following dual channel settings, which
have no limit on the length of time that inputs can be discrepant, an Input fault
will not occur for any discrepant condition or for any “cycle inputs required”
condition.
• 1 = Dual-channel equivalent (2NC)
• 3 = Dual-channel complementary (1NC + 1NO)
For all input settings except Dual-channel SS equivalent 3 s (2 OSSD 3s), if one
or two channels are connected to a 24V DC source other than terminals S11 and
S21, a fault occurs.
I/O faults are Stop Category faults, which initiate the configured Safe Stop Type.
I/O faults are latched until the safety option is successfully reset.
For more information on I/O faults, refer to
.
When using a dual-channel complementary (1NC + 1NO) device, the normally-
open input must be connected to the second input, as shown in the illustration.
For example, if the door is open when the input is ON, the normally-open
contact must be the second input (Input 1).
Channel 0
Active
Inactive
Channel 1
Active
Inactive
Evaluated Status
ON
OFF
Cycle Inputs Required