User`s manual

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MELSEC-Q
9 CONTROL OPERATION INSTRUCTIONS
Specified position Symbol Name Recommended range
*1
Unit Data format
Standard
value
Store
D2
+26
+27
PH
Upper limit alarm
set value
RL to RH
Real
number
100.0 U
+28
+29
PL
Lower limit alarm
value
RL to RH
Real
number
0.0 U
+30
+31
HH
Upper upper limit
alarm value
RL to RH
Real
number
100.0 U
+32
+33
LL
Lower lower limit
alarm value
RL to RH
Real
number
0.0 U
+40
+41
HS
Upper/lower limit
alarm hysteresis
0 to 999999 %
Real
number
0.0 U
+42
+43
CTIM
Change rate alarm
Check time
0 to 999999 Note that
32767
CTIM
T
s
Real
number
0.0 U
Loop tag
memory
*2
+44
+45
DPL
Change rate alarm
value
0 to 100 %
Real
number
100.0 U
D2
+96
Loop tag
past value
memory
*2 *3
+127
Used by the system as a work area. S
*1: The data of the item(s) where the values within the recommended range are given in the parentheses are stored by the system.
Users cannot set the data.
*2: The loop tag memory and loop tag past value memory occupy a total of 128 words. (Refer to Section 3.3.1 for details.)
*3: The applications of the loop tag past value memory are indicated below.
Specified position Description
D2
+96 Change rate monitor counter initial preset flag
+97 Change rate monitor counter
+126
+127
E1
n-m
When control is to be started from the initial status, the data must be cleared with the sequence program.
(2) Execution cycle ( T)
Set the execution cycle in SD1500 and SD1501 as real numbers.
Processing contents
(1) Engineering value reverse conversion
The following operations are performed to match the upper limit alarm value (PH), lower limit
alarm value (PL), upper upper limit alarm value (HH) and lower lower limit alarm value (LL)
ranges with the input value (E1).
(PH
RL
100
PH'
RH
RL),
(PL
RL
100
PL'
RH
RL)
(HH
RL
100
HH'
RH
RL),
(LL
RL
100
LL'
RH
RL)