Omron SRM1 - PROGRAMING 02-2001, Руководство по программированию

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7-15 Section Timer and Counter Instructions
389
Note that “TIM 000” is used to designate the TIMER instruction defined with TC
number 000, to designate the Completion Flag for this timer, and to designate
the PV of this timer. The meaning of the term in context should be clear, i.e., the
first is always an instruction, the second is always a bit operand, and the third is
always a word operand. The same is true of all other TC numbers prefixed with
TIM or CNT.
An SV can be input as a constant or as a word address in a data area. If an IR
area word assigned to an Input Unit is designated as the word address, the Input
Unit can be wired so that the SV can be set externally through thumbwheel
switches or similar devices. Timers and counters wired in this way can only be
set externally during RUN or MONITOR mode. All SVs, including those set ex-
ternally, must be in BCD.
7-15-1 TIMER – TIM
N
TC number
Ladder Symbol
Definer Values
SV : Set value (word, BCD)
IR, SR, AR, DM, HR, LR, #
Operand Data Areas
TIM N
SV
SV is between 000.0 and 999.9. The decimal point is not entered.
Each TC number can be used as the definer in only one TIMER or COUNTER
instruction. TC numbers run from 000 through 255 in the CPM2A/CPM2C PCs
and from 000 through 127 in the CPM1/CPM1A/SRM1(-V2) PCs.
TC 000 through TC 003 (TC 000 through TC 015 in the CPM2A/CPM2C) should
not be used in TIM if they are required for TIMH(15). Refer to
7-15-2 HIGH-
SPEED TIMER – TIMH(15) for details.
In the CPM2A/CPM2C PCs, TC 004 through TC 007 should not be used in TIM if
they are required for TMHH(––). Refer to
7-15-3 VERY HIGH-SPEED TIMER –
TMHH(––) for details.
A timer is activated when its execution condition goes ON and is reset (to SV)
when the execution condition goes OFF. Once activated, TIM measures in units
of 0.1 second from the SV.
If the execution condition remains ON long enough for TIM to time down to zero,
the Completion Flag for the TC number used will turn ON and will remain ON
until TIM is reset (i.e., until its execution condition is goes OFF).
The following figure illustrates the relationship between the execution condition
for TIM and the Completion Flag assigned to it.
Execution condition
Completion Flag
ON
OFF
ON
OFF
SV SV
Timers in interlocked program sections are reset when the execution condition
for IL(02) is OFF. Power interruptions also reset timers. If a timer that is not reset
under these conditions is desired, SR area clock pulse bits can be counted to
produce timers using CNT. Refer to
7-15-5 COUNTER – CNT for details.
Limitations
Description
Precautions