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FX Series Programmable Controllers Points Of Technique 10
10-26
10.16 Additional PID functions
The followin
g
parameter table
g
ives the additional parameters available with FX
2N(C)
MPUs.
These are:
-S
3
+1 bit 4: Pre-tunin
g
operation fla
g
.
-S
3
+1 bit 5: Output Value ran
g
e limit fla
g
.
-S
3
+22: Output Value upper limit.
-S
3
+23: Output Value lower limit.
For the full list of other parameters refer to pa
g
e 5-102.
Note: S
3
+1 b2 and b5 should not be active at the same time. Onl
y
one value each is entered
into the data re
g
isters S3+22 and S3+23.
10.16.1 Output Value range control (S
3
+1 b5)
Bit 5 of parameter S
3
+1, when ON, activates S
3
+22 and S
3
+23 to be upper and lower limits for
the output value (MV).
This feature restricts the output value to the specified limits; in effect, this automaticall
y
performs the same operation as that described in section 10.15.1.
Param-
eter
S
3
+ P
Parameter
name/func-
tion
Description
Setting
range
S
3
+1
Action-reac-
tion
direction and
alarm control
b0
Forward operation(0),
Reverse operation (1)
Not
applicable
b1 Process Value (
S
2
) chan
g
e alarm OFF(0)/ON(1)
b2 Output Value (
MV
) chan
g
e alarm OFF(0)/ON(1)
b3 Reserved
b4 Activate pre-tunin
g
(auto resets on completion)
b5 Output Value
(MV)
ran
g
e limit OFF(0)/ON(1)
b6-15 Reserved
S
3
+22
Output Value,
maximum
positive
chan
g
e alarm
Active
when
S
3
+1, b2
is set ON.
This is an alarm for the quantit
y
of positive chan
g
e
which can occur in one PID scan. If the Output
Value
(MV)
exceeds this value, bit
S
3
+24, b2 is
set
0 to 32767
Output Value,
Upper limit
restriction
Active
when
S
3
+1, b5
is set ON.
This is an upper limit for the Output Value
(MV)
.
Durin
g
operation the PID instruction restricts the
output so that it does not exceed this limit.
-32768 to
32767
S
3
+23
Output Value,
maximum
ne
g
ative
chan
g
e alarm
Active
when
S
3
+1, b2
is set ON.
This is an alarm for the quantit
y
of ne
g
ative
chan
g
e which can occur in one PID scan. If the
Output Value
(MV)
falls below this value, bit
S
3
+24, b3 is set.
0 to 32767
Output Value,
Lower limit
restriction
Active
when
S
3
+1, b5
is set ON.
This is a lower limit for the Output
Value
(MV)
.
Durin
g
operation, the PID instruction restricts the
output so that it does not fall below this limit.
-32768 to
32767