GE VersaMax PLC, User Manual

Page: 145 / 318

Input/ Output
Choices
Description
Reset flow
The Reset input can be used to select a specific step in the sequence.
When Enable and Reset both receive power flow, the function copies
the Preset Step value in the Control Block to the active Step
reference, also in the Control Block. Then the function block copies
the value in the Preset Step reference to the Out reference bits. When
Reset is active, the function ignores the Step input.
Pattern R, AI, AQ
The starting address of an array of words, each representing one step
of the Drum Sequencer. The value of each word represents the
desired combination of outputs for a particular value of Active Step.
The number of elements in the array is equal to the length input.
Dwell Time
R, AI, AQ,
none
This optional input array of words has one element for each element in
the Pattern array. Each value in the array represents the dwell time for
the corresponding step of the Drum Sequencer in 0.1 second units.
When the dwell time expires for a given step the Dwell Timeout bit is
set.
If a Dwell Time is specified the drum cannot sequence into its next
step until the Dwell Time has expired.
Fault Timeout
R, AI, AQ,
none
This optional input array of words has one element for each element in
the Pattern array. Each value in the array represents the fault timeout
for the corresponding step of the Drum Sequencer in 0.1 second units.
When the fault timeout has expired the Fault Timeout bit is set.
Control Block R
The beginning reference address of the function’s parameter block.
The length of the Control Block is 5 words. A more complete
description of what is contained within this block is listed below.
Length
CONST
Value between 1 and 128 that specifies the number of steps.
ok
flow, none
OK is energized if Enable is On and no error condition is detected. If
Enable is Off, this output will always be Off.
OUT
I, Q, M, T, G,
R, AI, AQ
A word of memory containing the element of the Pattern Array that
corresponds to the current Active Step.
Drum Coil
I, Q, M, T, G,
none
This optional bit reference is set whenever the function block is
enabled and Active Step is not equal to Preset Step.
Dwell Timeout
I, Q, M, T, G,
none
This optional bit reference is set if the dwell time for the current step
has expired.
Timeout Fault
I, Q, M, T, G,
none
This optional bit reference is set if the drum has been in a particular
step longer than the step’s specified Fault Timeout.
First Follower
I, Q, M, T, G,
none
This optional array of bits has one element for each step of the Drum
Sequencer. No more than one bit in the array is On at any time and
that bit corresponds to the value of the Active Step
Instruction Set Reference GFK-1503E User Manual 145
For public disclosure