Mitsubishi Electric a2 Series Programming Manual page 57

α
2 Simple Application Controllers
FB Name
Schmitt
Trigger
[ST]
Hour
Meter
[HM]
Speed
Detect
[SPD]
PWM
[PWM]
PID
Retentive
Alternate
[RAL]
Addition
[ADD]
Subtractio
n
[SUB]
FB Symbol Description of Function Block
T h e S c h m i t t Tr i g g e r F u n c t i o n B l o ck
0 0 0
compares an input value to preset high and
I P O low limits. The output is ON when the input
value reaches the high limit and then falls
S T below the lower limit. The function only
processes the data when the function block
is receiving an input signal.
The Hour Meter Function Block holds the
0 0 0
output status ON for a maximum of 32767
I P O hours, 59 minutes and 59 seconds. If the
input pin is turned OFF the elapsed time
C
H M will hold its value until either the clear pin
resets the time or the input pin is turned ON
again.
The Speed Detect Function Block is used to
count the incoming pulses max. 20Hz (with
I 0 0 0
an extension module max. of 1kHz) for a
U P O
set period of time. The upper and lower
C
limits can be set from -32768 to +32767
S P D
and the Period interval's set range is 1 to
32767 in 10ms increments.
The Pulse Width Modulation Function Block
changes the output status according to a
0 0 0
set period of time with a minimum of 100ms
I P O
a n d a m a x i m u m o f 3 2 7 6 7 0 0 m s i n
increments of 100ms. The percentage duty
P W M
for the function controls the amount of
elapsed time before the output status is
changed.
T h e P I D F u n c t i o n B l o c k i s t h e
A 0 0 0
E 0 0 0
implementation of PID, a control method
E P O
A P O
used to obtain stable control over a system
C variable. It is a equipped with an Auto-
C
P I D
P I D tuning function, which automatically adjusts
the Function Block parameters for the
specific application.
The Alternate Function Block is used to
reverse the ON and OFF state of the output
as and when the input pin receives a signal.
0 0 0
The output will be set ON when the input
I O
pin goes high and remain ON until the input
C
receives the second rising edge. When the
R A L
power is turned OFF the function block will
use the last alternation operation to control
the output.
0 0 0
I P O
T h e A D D F u n c t i o n B l o ck i s u s e d t o
summate two input values
A D D
0 0 0
I P O
The SUB Function Block is used to subtract
two input values.
S U B
Function Blocks 6
Memory
Section
Use
19 Byte 6.18
19 Byte 6.19
25 Byte 6.20
16 Byte 6.21
α
2
52 Byte 6.22
13 Byte 6.23
20 Byte 6.24
20 Byte 6.25
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