Rockwell Automation 1772-LS_LSP,D17726.8.6 PROG/OPER MANUAL-MINI PLC-2/05 - Manual (Page 265)

Quick Reference
Appendix C
CĆ9
Table C.H
Counter Instructions
NOTE: The counter word address, XXX, is assigned to the counter accumulated area of the data table. To determine which addresses are
valid accumulated areas, the most significant digit in the word address must be an even number.
Bit 14 is the overflow/underflow bit.
Bit 15 is the count complete bit.
Bit 16 is the enable bit for the CTD instruction.
Bit 17 is the enable bit for the CTU instruction.
The word address displayed will be 3 or 4 digits long depending on the data table size. When entering the word address, use a leading
zero if necessary.
Key Symbol Instruction Name 1770-T3 Display Rung Conditions Status Bits
-(CTU)- Up Counter XXX
-(CTU)-
PR YYY
AC ZZZ
Each time the rung goes true, the
accumulated value is incremented
one count. The counter will
continue counting after the preset
value is reached.
The accumulated value can be
reset by the CTR instruction.
When the rung is true:
bit 14-set if AC>999
bit 15-set when AC>PR PR
bit 17-set
When the rung is false:
bits 14-15-retained if it was set
bit 17-reset
-(CTR)- Counter Reset XXX
-(CTR)-
PR YYY
AC ZZZ
XXX-Word address of the CTU is
resetting.
The preset and accumulated
values are automatically entered by
the industrial terminal.
When the rung is true, the CTU or
CTD accumulated value and
status bits are reset to 000.
When the rung is true:
bits 14-17-reset
When the rung is false: No action
is taken
-(CTD)- Down Counter XXX
-(CTD)-
PR YYY
AC ZZZ
Each time the rung goes true, the
accumulated value is decreased by
one count.
When the rung is true:
bit 14-set when AC<000
bit 15-set when AC<PR
bit 16-set
When the rung is false:
bits 14-15- retained if it was set
bit 16-reset