Allen-Bradley 1444-AOFX00-04RB, User Manual, Page: 59 / 550

Rockwell Automation Publication 1444-UM001D-EN-P - June 2018 59
Install the Dynamix 1444 Series Monitoring System Chapter 2
IMPORTANT • Speed signals that are replicated by an opto-isolated
output result in a 180 degree phase shift.
• Some amount of signal delay and phase lag occurs, and is
cumulative per series connected module. See Table 7 .
• For the same speed signal, configure the trigger slope
(positive or negative) the same on all modules including
when using the opto-isolated output to replicate the signal
between modules.
To minimize phase error, we recommend that the trigger
slope is set as the falling edge of the signal (negative).
• The recommended method of communicating speed
signals is to use the TSC over the module local bus
(terminal base interconnect) or from the TSCX buffered
outputs, as that source adds zero signal delay and no phase
lag.
Table 7 - Signal Delay and Phase Lag
Speed Trigger Source
Rising Edge Falling Edge
RPM Hz Delay Phase Lag Delay Phase Lag
6,000 100 40 μs 1.44 4 μs 0.144
30,000 500 7.2 0.7
120,000 2,000 28.8 2.88