PLC模拟量输入输出.doc

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云锋
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| 2010-09-10 16:19:10 楼主
现有压力变送器一只,量程0~6MPa,输出4~20mA,请选择CPU及AI/O模块,写出模拟量的输入输出程序00
maxeu:=+006
valeu:=DB10,DBD0
Network 2  convert setting in engineering units to analog output
in this example ,assume that pqw272 connects to a control value that is fully
closed at 0 V output ,and fully open at 10 V output .valve_pos is a number
between 0 and 100 ,indicating the valve open percentage
CALL FB 101 , DB101     //调模拟量输出量化子程序,unscale fromeu range to analog output range
valeu:=DB10,DBD20
mineu:=+000
maxeu:=+002
raw :=PQW272
call fc 10                         //调用压力换算程序 ,press conversion
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| 2010-09-10 20:51:29 8楼
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FC 10 :press conversion
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| 2010-09-10 21:25:13 9楼
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FB100 IN 的局部变量表
name
data type
address
initial
commet
raw
int

0
value from analog input card ,0..27648 range
mineu
real

+000
engineering unit value corresponding to 0 raw
maxeu
real

+006
eu value corresponding to 27648 raw
FB100 OUT 的局部变量表
name
data type
address
initial
commet
valeu
real

+000
rw ,scaled to engineering units
FB100 TEMP 的局部变量表
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name
data type
address
commet
rawdi
Dint

raw ,as 32-bit integer
rawr
Real

raw ,as floating point number
rngeu
Real

eu range
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| 2010-09-10 21:39:31 10楼
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FB100 :scale analog input to engineering units
converts integer analog input value from 0..27648 range to mineu..mineu range
.coversion equation is:
valeu =raw*<maxeu-mineu>/27648+mineu
Network 1 convert raw to real
 L #raw
ITD
T #rawdi
L #rawdi
DTR
T #rawr
Network 2  calcuate eu span
 L #maxeu
L #mineu
-R
T #rngeu
Network 3  convert rawr to eu range
 L #rawr
L +004
/R
T #rawr
L #rngeu
*R
T #rawr
.
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Network 4 add eu offset
 L #rawr
L #mineu
+R
T #valeu
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| 2010-09-10