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Once defined, a TC number can be designated as an operand in one or more of
certain set of instructions other than those listed above. When defined as a timer,
a TC number designated as an operand takes a TIM prefix. The TIM prefix is
used regardless of the timer instruction that was used to define the timer. Once
defined as a counter, the TC number designated as an operand takes a CNT
prefix. The CNT is also used regardless of the counter instruction that was used
to define the counter.
TC numbers can be designated for operands that require bit data or for operands
that require word data. When designated as an operand that requires bit data,
the TC number accesses the completion flag of the timer or counter. When des-
ignated as an operand that requires word data, the TC number accesses a
memory location that holds the PV of the timer or counter.
TC numbers are also used to access the SV of timers and counters from a Pro-
gramming Device. The procedures for doing so using the Programming Console
are provided in 7-1 Monitoring Operation and Modifying Data.
The TC area retains the SVs of both timers and counters during power interrup-
tions. The PVs of timers are reset when PC operation is begun and when reset in
interlocked program sections, but the PVs of counters are retained. Refer to
5-10 INTERLOCK and INTERLOCK CLEAR – IL(02) and ILC(03) for details on
timer and counter operation in interlocked program sections. The PVs of count-
ers are not reset at these times.
Note that in programming “TIM 000” is used to designate three things: the Timer
instruction defined with TC number 000, the completion flag for this timer, and
the PV of this timer. The meaning in context should be clear, i.e., the first is al-
ways an instruction, the second is always a bit, and the third is always a word.
The same is true of all other TC numbers prefixed with TIM or CNT.
3-9 LR (Link Relay) Area
The LR area is used as a common data area to transfer information between
PCs. This data transfer is achieved through a PC Link System.
Certain words will be allocated as the write words of each PC. These words are
written by the PC and automatically transferred to the same LR words in the oth-
er PCs in the System. The write words of the other PCs are transferred in as read
words so that each PC can access the data written by the other PCs in the PC
Link System. Only the write words allocated to the particular PC will be available
for writing; all other words may be read only. Refer to the PC Link System Manual
for details.
The LR area is accessible either by bit or by word. LR area word addresses
range from LR 00 to LR 63; LR area bit addresses, from LR 0000 to LR 6315. Any
part of the LR area that is not used by the PC Link System can be used as work
words or for SYSMAC NET Link or SYSMAC LINK Systems.
LR area data is not retained when the power is interrupted, when the PC is
changed to PROGRAM mode, or when it is reset in an interlocked program sec-
tion. Refer to 5-10 INTERLOCK and INTERLOCK CLEAR – IL(02) and ILC(03)
for details on interlocks.
LR Area Section 3-9