Honeywell Experion PKS User Manual page 154

7 DEVICE SUPPORT BLOCK (DSB)
User-defined value
0 - 100
NaN
0
Output channel behavior in various scenarios
The following table summarizes the behavior of AO and DO channels in various scenarios in R410.2 and later
and R410.1 or earlier.
Scenario
DSB is loaded for the first time.
DSB is reloaded.
FTE connection break between
controller and PGM.
Extended diagnostics report channel
failure.
Extended diagnostics report Module
failure.
An extended diagnostic overflow
condition exists but the DSB is not
configured to ignore extended
diagnostics overflow (the Ignore
Extended Diagnostic Overflow
check box is not selected).
Standard diagnostics report Station
Not Existent error.
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Description
• For AO channels, numeric initialization value defines
percentage value of the output.
– If you define the initial value as 0, the AO channel
initializes to 0.
– If you define a nonzero value as the initialization value,
the AO channel initializes the output value using the
range defined by the low and the high range of the
channel.
• For DO channels, initialization value 0 defines OFF state of
the channel and value 1 defines ON state of the channel.
If the initial value is defined as NaN, the output channels (AO
and DO) hold the last output value.
If the initial value is defined as 0, the AO channel initializes to
the low range defined for the channel and the DO channel is
cleared to 0 during all error scenarios.
Impact on AO/DO channel value in
Experion R410.2 and later
Clears to zero.
Drives values provided by the controller
for the connected PDCs.
• Holds the last value if the DSB is
configured to hold the last output
value.
• If the DSB is not configured to hold
the last output value, channel values
are initialized from the user-defined
values.
Clears to zero.
Clears to zero.
Clears to zero.
The channel values are initialized from
the user-defined values.
Attention
If you want the output to be initialized to a low range,
you must enter a small non-zero value like 0.001 as
the initialization value. This enables the channel
value to initialize to the low range defined for the
channel. This difference is meaningful if an AO
channel is in 4-20 mA current loop.
Impact on AO/DO channel value in
Experion R410.1 or earlier
Clears to zero.
Drives values provided by the controller
for the connected PDCs.
• Holds the last value if the DSB is
configured to hold the last output
value.
• If the DSB is not configured to hold
the last output value, channel values
clear to zero.
Clears to zero.
Clears to zero.
Clears to zero.
Clears to zero.