GE VersaMax PLC User Manual page 136

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136 GFK-1503E
For public disclosure
The reset input (R) overrides the enable (EN) and always resets the sequencer. When R is
active, the current step number is set to the value passed in via the step number parameter.
If no step number is passed in, step is set to 1. All of the bits in the sequencer are set to 0,
except for the bit pointed to by the current step, which is set to 1.
When Enable is active and Reset is not active, the bit pointed to by the current step
number is cleared. The current step number is incremented or decremented, based on the
direction parameter. Then, the bit pointed to by the new step number is set to 1.
The parameter ST is optional. If it is not used, the Bit Seqencer function operates as
described above, except that no bits are set or cleared. The function just cycles the current
step number through its legal range.
10.1.12.1 Memory Required for a Bit Sequencer
Each bit sequencer uses three words (registers) of %R memory to store the information:
word 1
length of sequence (in bits)
word 2
word 3
Word 3 (the control word) stores the state of the boolean inputs and outputs of its
associated function block, in the following format:
9 8
Reserved
OK (status output)
EN (enable input)
current step number
control word
6 5 4 3 2
7
1 0
VersaMax PLC User Manual