Set Value Specification Method; Cautions On Routines - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
2) When variable analog potentiometers (expansion board) are used
X000
X001
The analog value of the potentiometer No. 0 is converted into
binary 8-bit data, and a numeric value in the range from 0 to 255
is transferred to D0.
In this application example, the value of D0 is used as the set
value of a timer.
4.5.3

Set value specification method

1. Specifying a constant (K)
X003
2. Indirectly specifying a data register
X001
X003
4.5.4

Cautions on routines

1) Use timers T192 to T199 in subroutines and interrupt routines. These timers execute counting when a
coil instruction or END instruction is executed.
When such a timer reaches the set value, its output contact turns on when a coil instruction or END
instruction is executed.
Because general type timers execute counting only when a coil instruction is executed (Refer to "4.5.5
Details of timer operation and timer accuracy" below.), they do not execute counting and do not operate
normally if they are used in subroutines or interrupt routines in which a coil instruction is executed only in
a certain condition.
2) When a retentive timer for 1 ms pulses (T246 to T249) is used in a subroutine or interrupt routine, note
that its output contact turns on when the first coil instruction is executed after the retentive timer has
reached the set value.
volume
Read
number destination
FNC 85
K0 D0
VRRD
D0
T0
Example of application as analog timer
Constant
(decimal integer)
10-second timer
T10
K100
FNC 12
K100 D 5
MOV
D5 = K100
10-second
T10
D 5
timer
The value of a variable analog potentiometer
board which can be built in an FX
expansion board can be obtained as numeric
data in the range from 0 to 255 in accordance
with the scale position.
An obtained numeric value can be specified as
the indirectly specified value for a timer to make
a variable potentiometer type analog timer.
Use the FNC85 (VRRD) instruction to take the
value of a variable analog potentiometer into the
PLC.
→ For FNC85(VRRD), refer to Section 16.6.
Use the FNC86 (VRSC) instruction to take the
value of a variable analog potentiometer as a
numeric value in the range from 0 to 10.
→ For FNC86(VRSC), refer to Section 16.7.
T10 is a 100 ms (0.1 sec) type timer.
When the constant "100" is specified, T10 works as a
10-second timer (0.1 sec × 100 = 10 sec).
Turns on when T10 reaches the indirectly specified
value of the defined data register, previously set by a
digital switch.
Note that the set value of a latched (battery backed)
type register is not held correctly sometimes when the
battery voltage becomes low.
4 Devices in Detail
4.5 Timer [T]
1
PLC as an
3G
2
3
4
5
6
7
8
9
10
99