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Timer and Counter Instructions Section 5-16
instruction for which the TIM/CNT area is allowed. This is done by designating
the TIM/CNT number used to define that timer or counter to access the mem-
ory location that holds the PV.
Note that “TIM 000” is used to designate the TIMER instruction defined with
TIM/CNT 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 TIM/CNT
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 thumb-
wheel 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 externally, must be in BCD.
5-16-1 TIMER – TIM
Limitations SV is between 000.0 and 999.9. The decimal point is not entered.
The EM area is available in CQM1H-CPU61 CPU Units only.
Each TIM/CNT number can be used as the definer in only one TIMER or
COUNTER instruction.
TIM/CNT 000 through TIM/CNT 015 should not be used in TIM if they are
required for TIMH(15). Refer to 5-16-4 HIGH-SPEED TIMER – TIMH(15) for
details.
Description 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 TIM/CNT 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 condi-
tion for TIM and the Completion Flag assigned to it.
N: TIM/CNT number
#
Ladder Symbol
Definer Values
SV: Set value (word, BCD)
IR, SR, AR, DM, EM, HR, LR, #
Operand Data Areas
TIM N
SV
Execution condition
Completion Flag
ON
OFF
ON
OFF
SV SV
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