Input/Output Modules 97
Chapter 3 System Description
The PI Module has three independent input channels. Each input channel:
• Receives pulse input voltages from each point
• Converts the values to frequency (RPM) data
• Transmits the values to the MPs on demand
To ensure correct data for each scan, one value is selected using a mid-value
selection algorithm. Sensing of each input point is designed to prevent a single
failure on one channel from affecting another channel.
!
CAUTION
For critical control applications, we recommend using redundant sensors.
The PI Module sustains complete, on-going diagnostics for each channel. If the
diagnostics detect a failure on any channel, the Fault indicator is activated, which
in turn activates the system alarm. The Fault indicator points to a channel fault, not
a complete module failure. The PI Module is guaranteed to operate properly in the
presence of a single fault and may continue to operate properly with multiple faults.
The PI Module supports hot sparing for online replacement of a faulty module or
continuous back-up to an active module. The PI Module is mechanically keyed to
prevent improper installation in a configured baseplate.
To Next Page
Loading...