Timer Control Instructions - Hitachi SJ700-2 Series Instruction Manual

Chapter 5 Instruction Words

5.6 Timer Control Instructions

The easy sequence function of the inverter has a timer function that can be used in the following two
modes:
(1) Free-running timer mode
(2) Timer contact output mode (timer-start, timer-stop, and delay operations)
The timer function uses eight timer counter circuits that are configured as shown in the figure below.
<variable> or
<constant>
timer stop
instruction
timer set
instruction
delay on/delay
off instruction
Counting
cycle
(10 ms)
TC (k): Timer counter variable (up counter)
TD (k): Timer contact (one-shot timer)
The timer counter is a 31-bit up counter that runs in a 10-ms cycle (1 count per 10 ms), and operates as a
free-running timer when the execution of a easy sequence program is started.
When the timer set, delay on, or delay off instruction is executed, the timer counter is cleared and
restarted. While the timer counter is operating, its count is compared with the count specified by a
variable or constant to determine whether they match. When the counts match each other, the timer
counter stops counting.
When the timer off instruction is executed, the timer counter is cleared and restarted. Subsequently, the
timer counter operates as a free-running timer.
The
TC (0)
counter
starts.
Comparison
for matching
TD (0)
Y (00)
[PRN]
32 32
Comparison for
matching
Block diagram for timer function
2^31-1
delay on Y (00) TD (0) 1000
Example of timer function operation
Timer buffer (count)
32
≧
32
Up counter
CLR UP
(counting cycle:
10 ms)
1000
delay off Y (00) TD (0) 1500
5 - 20
In timer contact output mode
1
S Q
Latch
R
CLR
In free-running timer mode
32
2^31-1
1500
timer off TD (0)
TD (k)
TC (k)