IDEC microsmart pentra, Руководство по программированию

Страница: 55 / 344

FT1A S
MART
A
XIS
U
SER
’
S
M
ANUAL
FT9Y-B1382 5-9
5: B
ASIC
I
NSTRUCTIONS
Timer Circuit
The preset value 0 through 65535 can be designated using a data register D0 through D999 or D1000 through D1999; then the
data of the data register becomes the preset value. Directly after the TML, TIM, TMH, or TMS instruction, the OUT, OUTN, SET,
RST, TML, TIM, TMH, TMS, TMLO, TIMO, TMHO, or TMSO instruction can be programmed.

Timedown from the preset value is initiated when the operation result directly before the timer input is on.

The timer output turns on when the current value (timed value) reaches 0.

The current value returns to the preset value when the timer input is off.

Timer preset and current values can be changed using WindLDR without downloading the entire program to the CPU again. From the
WindLDR menu bar, select
Online > Monitor > Monitor , then Online > Custom > New Custom Monitor .

If a timer preset value is changed during timedown, the timer remains unchanged for that cycle. The change will be reflected in the next time
cycle.

If a timer preset value is changed to 0, then the timer stops operation, and the timer output is turned on immediately.

If a current value is changed during timedown, the change becomes effective immediately.

For the data movement when changing, confirming, and clearing preset values, see page 5-18. Preset values can also be changed and
changed preset values can be confirmed using the LCD and push buttons. See pages 5-63 and 5-65.

WindLDR ladder diagrams show TP (timer preset value) and TC (timer current value) in advanced instruction devices.
Timer Accuracy
Timer accuracy due to software configuration depends on three factors: timer input error, timer counting error, and timeout output
error. These errors are not constant but vary with the user program and other causes.
Timer Input Error
The input status is read at the END processing and stored to the input RAM. So, an error occurs depending on the timing when the
timer input turns on in a scan cycle. The same error occurs on the normal input and the catch input. The timer input error shown
below does not include input delay caused by the hardware.
Caution
I1
Ladder Diagram
TIM
D10
T5
Q0

For restrictions on ladder programming of
timer instructions, see page 5-32.
LOD
TIM
OUT
I1
T5
D10
Q0
Program List
Instruction Data
Program Processing
Actual Input
ON
OFF
Input RAM
ON
OFF
Timer Start
Minimum Error
Tie
END
1 scan time
TIM END
Tet
Program Processing
Actual Input
ON
OFF
Input RAM
ON
OFF
Timer Start
Maximum Error
END
1 scan time
TIM END
Tet
TIM
Tie
When the input turns on immediately before the END
processing, Tie is almost 0. Then the timer input error is only
Tet (behind error) and is at its minimum. When the input turns on immediately after the END processing,
Tie is almost equal to one scan time. Then the timer input error is
Tie + Tet = one scan time + Tet (behind error) and is at its
maximum.
Tie: Time from input turning on to the END processing 
Tet: Time from the END processing to the timer instruction execution