Owner's manual

Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 11
Chapter 2
Module Operation
Counters 0…7
Counters 0…7 on the module are dedicated to up and down counting of
incoming pulses. The module counts rising pulse edges at a maximum of 40 kHz.
However, the following limitations apply as shown in Figure 1
:
• The duration of a pulse cannot be less than 11 μs, which is the minimum
hardware delay time for a transition to be detected by an input.
• For repetitive counting, the total cycle time cannot be less than 25 μs.
Figure 1 - Pulse Cycle Limits
For complete specifications, refer to the 1756 ControlLogix I/O Modules
Specifications Technical Data, publication 1756-TD002
.
Topic Page
Counters 0…7 11
Counter Control Functions 15
Output Control 23
11 µs
25 µs