Allen-Bradley ProcessLogix 1756-IA16, Reference Manual, Page: 73 / 120

Publication 1757-RM810A-EN-P - May 2002
Functional Blocks 3-33
FANOUT
Description Uses one input and provides up to eight initializable outputs. It may also have up to eight secondaries, since there is
one secondary per initializable output. You may specify a separate gain, bias, and rate for each output. Each specified
value can be fixed or external. A fixed value is stored manually or by a program, and an external value is brought from
another function block. This block calculates a separate floating bias for each output following an initialization or
mode change. This provides a "bumpless" transition for each output.
Function Provides a “bumpless” output for each of up to 8 outputs following initialization or mode changes.
Timeout
Monitoring In cascade mode, performs timeout monitoring on X1. If the X1 value is not updated within a predefined time, this
block invokes the following timeout processing.
1. Sets the “input timeout” flag (TMOUTFL).
2. Sets the input value to Bad (NaN).
3. Requests the X1 primary to initialize (through BACKCALCOUT).
This block does not support mode shedding on timeout.
Input X1 = initializable input which must come from another function block; an operator cannot set it.
XEUHI and XEULO define the full range of X1:
XEUHI represents the 100% of full scale value.
XEULO represents the 0% of full scale value.
Outputs May have up to 8 initializable outputs as follows:
•
OP [1..8] = Calculated output in percent.
•
OPEU [1..8] = Calculated output in engineering units.
Note that the default OP [1], [2] connection pins are exposed on the blocks and the implicit/hidden connection
function automatically makes the appropriate value/status parameter (OPX [1..8]/OPEUX [1..8]) connection when
required.
Output Ranges CVEUHI [1..8] and CVEULO [1..8] define the full range of CV [1..8] in engineering units -- block has separate output
range for each output based on the input range of each secondary.
•
OPHILM and OPLOLM define the normal high and low limits for OP as a percent of the CV range; these are
user-specified values -- the same limits apply to all outputs. An operator may store an OP value that is outside
these limits.
•
OPEXHILM and OPEXLOLM define the extended high and low limits for OP as a percent of the CV range; these are
user-specified values -- the same limits apply to all outputs and operator is prevented from storing an OP that
exceeds these limits.
Windup
Processing If all secondaries are in high windup, block propagates a high windup status to its primary (ARWNET [1..8] = Hi)
If all secondaries are in low windup, block propagates a low windup status to its primary (ARWNET [1..8] = Lo)
If at least one secondary has a normal windup status or is in high windup and another is in low, block propagates a
normal windup status to its primary.
If the gain is reversed for one of the outputs, then high windup on that output is the same as low windup on the
others.
Parameters on following page
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