27
TC numbers are also used to access the SV of timers and counters from a
Programming Device. The procedures for doing so from the Programming
Console are provided in
7–8 Monitoring Operation and Modifying Data.
The TC area retains the SVs of both timers and counters during power inter-
ruptions. The PVs of timers are reset when PC operation is begun and when
reset in interlocked program sections. Refer to
5–7 Interlock and Interlock
Clear – IL(02) and ILC(03)
for details on timer and counter operation in inter-
locked program sections. The PVs of counters are not reset at these times.
Note that in programming “TIM 00” is used to designate three things: the
Timer instruction defined with TC number 00, the Completion Flag for this
timer, and the PV of this timer. The meaning in context should be clear, i.e.,
the first is always 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. In explanations of ladder diagrams, the Completion Flag and PV ac-
cessed through a TC number are generally called the Completion Flag or the
PV of the instruction (e.g., the Completion Flag of TIM 00 is the Completion
Flag accessed through TC number 00, which has been defined using TIM).
When the RDM(98) (Reversible High-speed Drum Counter) is used TC 46 is
used as the present value storage area of the counter and thus cannot be
used for any other purpose.
3–8 TR Area
The TR area provides eight bits that are used only with the LD and OUT in-
structions to enable certain types of branching ladder diagram programming.
The use of TR bits is described in
Section 4 Programming
.
TR addresses range from TR 0 though TR 7. Each of these bits can be used
as many times as required and in any order required as long as the same TR
bit is not used twice in the same instruction block.
TR Area Section 3–8
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