Rockwell Automation 1772-LP3 PLC - 2/30 Programmable Controller Programming and Operations Manual - Manual (Page 332)

Appendix
C
CĆ1
Programming .01ĆSecond Timers
The bulletin 1772 Mini-PLC-2 Programmable Controller permits you to
enter On Delay Timer (TON), Off Delay Timer (TOF), and Retentive
Timer (RTO) instructions
1 with a 0.01-second time base. These are also
referred to as 10-millisecond (10-msec) timers.
Timers with a 10-msec time base provide you with greater timing
resolution and accuracy than is possible with a 0.1-second time base.
Ten-msec timers are used when time delays from 0.02 to 9.99 seconds are
required.
When you enter a timer instruction into a program, you must specify the
following:
Timer word address
Time
base
Preset value
Accumulated value (for RTO only)
Note that your selection of preset value and time base is closely related.
The processor executes the time-delay functions by incrementing the timer
accumulated values one unit for each time base unit that elapses. In other
words, the preset value represents a specific number of increments of the
time base.
Note, however, that the preset value is not an absolute length of time. For
example, if the preset value is 010, the time delay will be:
10 seconds if a 1.0-second time base is selected
1.0 second if a 0.1-second time base is selected
0.10 second if a 0.01-second (10-msec) time base is selected
The smaller the time base, the larger the preset value must be to obtain
the same time delay. For example, to obtain a 5-second time delay, the
program would contain:
005 in preset for a 1.0-second time base
050 in preset for a 0.1-second time base
500 in preset for a 0.01-second time base
1 In order to enter these instructions, a Series B or later Bulletin 1772ĆPLCĆ2 Program Panel must be used. Alternatively, a Series B
or later Bulletin 1772ĆPLC/PLCĆ2 Program Panel adapter and a Series C or later Bulletin 1774ĆPLC Program Panel may be used.
C.0
Introduction
C.1
Time Base Selection