Rockwell Automation 1771-IJ_IK IK ENCODER/COUNTER MODULES - Manual (Page 48)

6–4 Block Transfer Programming
Publication 1771ĆUM006B-EN-P - June 2002
Preset Words
In block transfer communication, preset words #1 and #2 have the
format of Figure 6.2. Here bits 00-13 store the preset value. When
BCD operation has been selected, these bits may represent a value
from 000-999. When 12-bit binary operation has been selected, the
value may range from 0 to 1111 1111 1111 binary (4095 decimal). A
module switch selection is made during installation to select either
BCD or binary mode.
Figure 6.2
Preset Words Ć Block Transfer Mode
17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00
Most
Significant
BCD Digit
(0-9)
Middle
(0-9)
Least
Significant
(0-9)
Preset Value
or, 12-bit binary value
AC > PR
AC = PR
AC < PR
Bit 14,
Not used
15961
Bits 15Ć17,
Comparison Parameters for
Preset Value
BCD Digit
BCD Digit
1
1
1
1
1 Module switch delection determines whether bits 00Ć13 are of binary or BCD format
Note: If BCD operation has been selected, only BCD digits should
be entered in the data table word output to the module. If non-BCD
digits are entered in a preset value, the module sets its default preset
value to 000 for that word.
Bits 15-17 establish the comparison to be made by the module
between its accumulated count and each preset value. When any of
these bits are set to 1, the module makes the indicated comparison
between its accumulated count and the appropriate preset word
value. When the comparison is true, the corresponding output of the
module may be energized. Of course, the enable outputs bit in the
control word must also be set to 1 for outputs to be energized.
As Figure 6.2 shows, one bit is used for each comparison parameter:
less than, equal to, or greater than. Note that more than one of these
bits can be set to 1 for each preset, allowing such combinations as
less than or equal to, greater than or equal to, or not equal to.
Bit 14 of each preset word is not used. It may be 1 or 0.