Rockwell Automation AADvance Controller Demo Unit - Manual (Page 80)

Demo Unit User Manual (AADvance Controller)
5-14 Document: 553850 Issue 1.2: March 2011
Note: (†) Discrepancy can only be reported TRUE when two or three modules are
active in a group. (††) The voltage element cannot report values below 0mV.
Faulted State for Digital Inputs
A digital input channel is faulted (the state reports a value of 7) when the channel is
incapable of reporting a voltage within a safety accuracy specification of 10% of the full
scale measurement of the 24V dc supply (2.4V).
When the state reports the value 7, then the following 'safe' values are reported by the
other variables:
Input State = FALSE
Line Fault = TRUE
Discrepancy = TRUE
Channel Fault = TRUE
Voltage = 0mV
About Threshold Values for Digital Inputs
The module determines the channel state and the line fault status by comparing the
channel input voltage with defined threshold values. You can define your own
threshold values or use a set of default values. The values you choose for the module
are inherited by each channel; you can define different thresholds for individual
channels later.
An indeterminate region is defined between the closed and open status to allow for
marginal faults in the external wiring or sensor.
Note: When the system is operational you should change these values only through
an on-line update.
The AADvance controller provides hysteresis on the thresholds for increasing and
decreasing values to prevent chatter. The Workbench updates the reporting values
during every application cycle.