Rockwell Automation 1794-VHSC 1794 FLEX I/O Very High Speed Counter Module User Manual - Manual (Page 41)

Rockwell Automation Publication 1794-UM010D-EN-E - July 2013 33
Communicate With Your Module
Communication Fault Behavior
You can configure the 1794-VHSC response to a communication fault. Upon
detection of a communication fault, the module can:
• leave the module output data in its last state (hold last state)
• reset the module output data to zero (reset)
• apply safe state data to the module output
Idle State Behavior
The 1794-VHSC module responds to idle state according to the
Communication Fault Behavior described above. The module can:
• leave the module output data in its last state (hold last state)
• reset the module output data to zero (reset)
• apply safe state data to the module output
Input Data Behavior upon Module Removal
I/O module input data sent by the adapter upon module removal is configurable.
The adapter can:
• reset the module output data to zero (reset)
• leave the module output data in the last state before module removal (hold
last state)
Frequency/Resolution Enhancement
This mode is only for use in modules with firmware revision D or later.
Frequency/Resolution Enhancement is a precise configuration which handles the
decimal position adjustment to frequency count. Using this mode allows the
module to read the frequency up to two positions to the right or left of the
decimal place. For example, a rounded frequency of 13 Hz can be displayed as
1257 or 12.57. The mode is only valid when the module is configured for Period
Rate or Continuous Rate.
Frequency Resolution/Enhancement reports the frequency back as a floating
point value in a single word and allows configuration of decimal places of
resolution.
The upper byte of the counter control word (output word 0) is reserved for
special mode, Enhancing Frequency/Resolution. In this mode, you can change
significant digits of frequency display based on output word 2 for channel 0 and
output word 3 for channel 1. Decimal point placement is absolute positioning. -2